Re: [PSES] Couple of loosely related safety questions

[Richard Nute]

 

 

Hi Brian:

 

This does not answer your questions, but MAY give you an analysis tool:

 

CLEARANCE is standards name for AIR INSULATION.

 

CREEPAGE DISTANCE is standards name for DISTANCE ACROSS THE SURFACE OF SOLID
INSULATION.

 

Hope to meet you at the Symposium!

 

Best regards,

Rich

 

 

From: Brian Gregory [mailto:brian_greg...@netzero.net] 
Sent: Friday, April 26, 2024 4:12 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Couple of loosely related safety questions

 

 

1.  Clearances for US Safety:  

 

I'd cite the relevant standards, but they are so alike (identical Clearance
tables), and so alike to UL 508, I'll defer.  Here's the question:

 

When citing clearance spacing from "uninsulated live components"  does one
measure from the edge of a PCB to the enclosure well, or only from the live
components, like a pad, or the bottom pin of a thru-hole cap?

1a.  what sort of passivation or RTV could make those live components not
"uninsulated"?

 

2.  Slots to increase creepage for high-voltage components

 

A FET that's rated for say 600V does not have to follow PCB-creepage rules
for 600V, is clearly stated places like UL 1741, §26.1.1 exception #8.  For
other components, like say 1000V caps in 0805 packages or FET driver chips
the requirements aren't as clear.  Is a slot needed to maintain creepage or
not if the component is properly rated?  It does appear from a TI support
page for dual-bridge converters, that slots are recommended in order to
prevent contamination that may compromise the components isolation
performance.

 

My gut says:  no, slots are not needed between component terminals on a PCB,
but could be recommended for sensitive parts, like FET drivers.

 

Thoughts? 

 

Colorado Brian 

 

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Re: [PSES] Couple of loosely related safety questions

[Richard Nute]

 

Hi Brian:

 

You should attend the IEEE PSES Symposium in Chicago next week to get the
answers to these questions from experts.  Lots of experts in clearance and
creepage will be there and will be happy to provide you with answers!

 

Best regards,

Rich

 

 

From: Brian Gregory [mailto:brian_greg...@netzero.net] 
Sent: Friday, April 26, 2024 4:12 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Couple of loosely related safety questions

 

 

1.  Clearances for US Safety:  

 

I'd cite the relevant standards, but they are so alike (identical Clearance
tables), and so alike to UL 508, I'll defer.  Here's the question:

 

When citing clearance spacing from "uninsulated live components"  does one
measure from the edge of a PCB to the enclosure well, or only from the live
components, like a pad, or the bottom pin of a thru-hole cap?

1a.  what sort of passivation or RTV could make those live components not
"uninsulated"?

 

2.  Slots to increase creepage for high-voltage components

 

A FET that's rated for say 600V does not have to follow PCB-creepage rules
for 600V, is clearly stated places like UL 1741, §26.1.1 exception #8.  For
other components, like say 1000V caps in 0805 packages or FET driver chips
the requirements aren't as clear.  Is a slot needed to maintain creepage or
not if the component is properly rated?  It does appear from a TI support
page for dual-bridge converters, that slots are recommended in order to
prevent contamination that may compromise the components isolation
performance.

 

My gut says:  no, slots are not needed between component terminals on a PCB,
but could be recommended for sensitive parts, like FET drivers.

 

Thoughts? 

 

Colorado Brian 

 


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Re: [PSES] 61010-1 hazardous live classification

[Richard Nute]

 

Hi James:

 

In the pulse mode, 46 volts peak exceeds the 42.4 volts peak limit.  In
accordance with the 61010 standard, the voltage cannot be accessible in the
pulse mode.

 

However, the pulse mode is dc (the current does not reverse).  The RMS of
such a pulse is 46 times the square root of the duty cycle.  The shorter the
duty cycle, the less human sensation of the pulse.  Chances are that the
pulse is not detectable by a human finger any more than 60 volts DC.  But
the standard does not allow such a determination.  

 

You are stuck.

 

Best regards,

Richard Nute

Bend, Oregon, USA

 

 

From: James Pawson (U3C)  
Sent: Monday, February 26, 2024 5:38 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] 61010-1 hazardous live classification

 

Hello all,

 

I hope this safety question is a fairly simple one for you, it being Monday
after all.

 

1.  A piece of equipment with a power supply output for driving a lamp.
It has two modes, DC and pulsed.
2.  Both of the output voltage connections are on accessible terminals
(checked using finger probe)
3.  Classifying voltages as per EN 61010-1 clause 6.3.1 (limit values
for accessible parts, normal operating conditions)
4.  DC mode runs at 46Vdc maximum. This is less than 60Vdc so is not
Hazardous Live
5.  Pulse mode runs at 46Vdc pulsed (frequency up to 1kHz, duty cycle
can vary down to 0.01%) which is an AC waveform greater than 42.4V peak so
is Hazardous Live
6.  The output from the equipment is low impedance so is more than
capable of sourcing the required 0.7mA through the IEC 60990 body model.

 

Quick sketch attached to illustrate the concept. I even ran a SPICE
simulation to make sure I wasn't getting something wrong.

 

I would appreciate the sanity check!

 

All the best

James

 


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[PSES] Household safety in the Internet era

[Richard Nute]

For those who use IEC 60335. here is a superficial (and non-technical) look.

https://etech.iec.ch/issue/2024-01/household-safety-in-the-internet-era

Richard Nute
Bend, Oregon, USA

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Re: [PSES] 61010-1 Stability test, Para 7.4 Stability

[Richard Nute]

 

Hi Steve:

 

In studying other standards, some have specified toppling, such as exceeding 15 
degrees (IEC 62368-1, 4th ed., 8.6.5) or exceeding 10 degrees (IEC 62368-1, 2nd 
ed., 8.6.2.2).  On the other hand, IEC 60335, 4th ed., has no such stability 
requirement that I could find.  (By the way, the same requirement as in 1010 is 
in IEC 60950-1.)  

 

If a redesign is warranted, I suggest spring-mounting the mast such that a 
toppling force is not transmitted to the base.

 

Richard Nute

Bend, Oregon, USA

 

Ps:  It is clear that the requirement assumes a monolithic construction.  


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Re: [PSES] Reduce Speed of Moving Part to Reduce Risk

[Richard Nute]

 

Hi Doug and Brian:

 

I thought I would offer my (radical) point of view on the issue of “speed of 
moving parts.”

 

Consider moving aluminum foil and moving aluminum block, both at the same 
speed.  The aluminum foil has very little mass, while the aluminum block has 
relatively high mass.  The foil is not likely to cause injury, while the block 
may cause injury.  

 

Consider an aluminum needle and an aluminum block, both having the same speed 
and mass.  The needle is likely to cause injury, while the block is not likely 
to cause injury.

 

Consider the time of contact with a moving part.  If the time is long, then 
injury is not likely.  If the time is short, then injury is likely.

 

So, in addition to speed, we must consider mass of the block, contact area, and 
duration of the contact in predicting injury.  

 

In other words, energy per area (mv2 per area in this case) whether mechanical, 
thermal, radiant, chemical, or electrical, transferred to a body part for a 
(usually short) period of time, causes injury.  The same energy magnitude 
transferred over a long period of time is not likely to cause injury.

 

An injury occurs only when energy per contact area of sufficient magnitude and 
duration is imparted to a body part.  Both the safety science article and the 
IRSST paper discuss energy of moving parts and area, but do not address the 
other parameters.  Both introduce (to me) the concept of “force” on various 
body parts.  I’m not sure of how this fits into this safety discussion.

 

Consideration of speed alone is over-simplification.

 

Best regards,

Rich

 

 

From: Doug Nix  
Sent: Monday, January 22, 2024 11:16 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Reduce Speed of Moving Part to Reduce Risk

 

Hi Brian,

 

In the machinery sector, 250 mm/s has long been used as the threshold for 
avoidability. This figure comes from the robot standards and has been used for 
about 30 years. Studies done at the Polytechnique de Montréal [1] and IRSST [2] 
have shown that a speed closer to 140 mm/s is more universally avoidable by 
people working in various environments, but the long use of 250 mm/s has 
entrenched that higher speed. Related to that is the IRSST’s Repoer R-956. I’ve 
attached copies of these documents for you.

 

You can find the 250 mm/s number quoted in most machinery safety standards 
where reduced speed is considered for risk reduction. The origin is in ANSI/RIA 
R15.06 1992, which made its way into CSA Z434 and then eventually to ISO 10218.

 

[1]  Y. Chinniah, B. Aucourt, and R. Bourbonnière, “Study of Machine 
Safety for Reduced-Speed or Reduced-Force Work R-956,” IRRST - Institut de 
recherche Robert-Sauvé en santé et en sécurité du travail, Montreal, 2017.

 

[2]  Y. Chinniah, B. Aucourt, and R. Bourbonnière, “Safety of 
industrial machinery in reduced risk conditions,” Safety Science, vol. 93, pp. 
152–161, Mar. 2017, doi: 10.1016/j.ssci.2016.12.002.

 

 

Best regards,

 

Doug Nix

d...@ieee.org  

+1 (519) 729-5704

 


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Re: [PSES] Products requiring dielectric voltage withstand test on RJ45 and XLR sockets

[Richard Nute]

 

 

Hi Chuck:

 

I don't know why your lab wants to do the primary-circuits-to-ground hi-pot
test to "unearthed socket terminals."  I assume your secondary circuits are
grounded, and, if so, the pins of sockets (RJ45 and XLR) are therefore
referenced to ground and are subject to the primary-to-ground voltage..
Same for USB terminals.  (If the RJ45 and XLR circuits are floating or if
your product is two-wire mains, then the respective circuits must be
grounded during the test.)

 

Of course you can do the accessibility test to the pins to show that they
are inaccessible.  However, I would assemble RJ45 and XLR mating connectors
with all pins connected together and attached to a wire whose far end is
grounded during the test.  This assures all the terminal pins are grounded
and meets the lab's requirement.  (Note that the product is non-operational
during the hi-pot test, so grounding all the pins does not damage the
product.)

 

I could not find justification for 3600 volts peak.  Can you justify this
test voltage in the standard?

 

Best regards,

Richard

Bend, Oregon, USA

 

 

From: Chuck August-McDowell  
Sent: Tuesday, January 16, 2024 4:33 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Products requiring dielectric voltage withstand test on RJ45
and XLR sockets

 

I'm working with a new lab and new product using IEC 62368-1 3rd Ed.

they are asking the company to perform production line test dielectric
voltage withstand test of 3600 Vp or DC 1 to 4 seconds on Ethernet port
connector RJ45 and Pro Audio XLR connector sockets?

"Between primary to other accessible conductive part- L/N of plus pins to
accessible unearthed socket terminals"

 

Can I use the IEC 62368-1 3rd Ed. blunt probe of Figure V.3 to show that the
pins are not accessible and need not be tested?

 

Anyone else must production line Hipot Ethernet port connector RJ45 or Pro
Audio XLR connector sockets?

 

Thank you for the help.

 

 

Chuck

 


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Re: [PSES] Is certification 'voided' by improper operational conditions?

[Richard Nute]

 

 

Hi Lauren:

 

The part was run for 8 hours at a temperature above its rated temperature.
Supposedly, the manufacturer's rated temperature is the maximum temperature
for "non-deterioration" of the part and its materials.  So, the part,
supposedly (and we must expect), has suffered some deterioration (e.g., may
not meet all of its specs) even though it may still be operational.

 

A circuit-breaker is a safeguard.  A circuit-breaker that has suffered some
deterioration may not work according to its rating.  It may not meet its
safeguard function.  I would not trust it as a safeguard.

 

For this reason, I would treat the safety certification as void, although,
for me, this is not the point.  

 

Of course, the circuit-breaker could be submitted for certification for a
higher rated temperature.  If it passes, then all is okay.

 

Best wishes for the New Year!

Rich

   

 

From: Lauren Crane <1afd08519f18-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, January 5, 2024 4:48 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Is certification 'voided' by improper operational
conditions?

 

Hello Experts, 

 

If I have UL certified component and operate it for a period of time outside
its specified conditions of operation, and then return the conditions to
specified levels, is it appropriate to still think of the component as
certified, or is the certification somehow voided by this accident? 

 

For example, a circuit breaker rated for 40degC max ambient run at 50degC
ambient for 8 hours and then ambient temp brought down to 30degC.  

 

Best Regards, 

-Lauren

 


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Re: [PSES] American Vs. European 30 Ground Fault Leakage Current Standards

[Richard Nute]

 

Hi Ronan:

 

GFEP North America:

https://www.eaton.com/us/en-us/skuPage.GFEP130.pdf

 

GFEP Europe:

https://library.e.abb.com/public/a9cd966c1794415d945b232fb2d7a9ee/1SXU430091
L0201_GFEP_Info_Tool.pdf

 

According to:

https://forums.mikeholt.com/threads/gfci-vs-gfep.116424/

"GFCI and GFPE have different trip thresholds and GFPE is for protecting
equipment not humans."

 

Richard

Bend, Oregon

 

 

From: Ronan Shanley <205e1cfd8f16-dmarc-requ...@listserv.ieee.org> 
Sent: Tuesday, November 21, 2023 11:37 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] American Vs. European 30 Ground Fault Leakage Current
Standards

 

Hello Experts,

 

Does anyone know if a GFEP breaker, that meets the USA standards, will meet
the EU standard for human protection? If not, why is that? What is the
difference between the USA and EU standards?

 

Best,

 

Ronan Shanley

Automation Engineer
SIO Electrical 
 

 


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Re: [PSES] The NPR news quiz

[Richard Nute]

 

The message was meant for my kids.  I don’t know how I sent it to PSES.  
Apologies.

 

Rich

 

From: Ken Javor  
Sent: Friday, November 10, 2023 4:03 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] The NPR news quiz

 

I didn’t know the answer to a single question. I feel smarter than if I had 
known any of the answers.  And I feel really smart not paying any attention to 
all of that.

 

-- 

Ken Javor

(256) 650-5261

 

From: Richard Nute mailto:ri...@ieee.org> >
Reply-To: mailto:ri...@ieee.org> >
Date: Friday, November 10, 2023 at 4:38 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Subject: [PSES] The NPR news quiz

 

 

Final score: 5/11. Lackluster.

 

 
<https://www.npr.org/2023/11/10/1211700159/donald-trump-election-debate-gop-animals-npr-news-quiz?utm_source=npr_newsletter_medium=email_content=20231110_term=9074533_campaign=news_id=61871060=151_att1=>
 
https://www.npr.org/2023/11/10/1211700159/donald-trump-election-debate-gop-animals-npr-news-quiz?utm_source=npr_newsletter_medium=email_content=20231110_term=9074533_campaign=news_id=61871060=151_att1=






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[PSES] The NPR news quiz

[Richard Nute]

Final score: 5/11. Lackluster.


https://www.npr.org/2023/11/10/1211700159/donald-trump-election-debate-gop-a
nimals-npr-news-quiz?utm_source=npr_newsletter_medium=email_content=
20231110_term=9074533_campaign=news_id=61871060=151_at
t1=






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Re: [PSES] UL1007 vs VW-1 Flammability ratings

[Richard Nute]

 

Hi Steve:

 

VW-1 is roughly equivalent to V-1 except applies to wire.

 

Richard

Bend, Oregon

 

From: Stephen Clarke [U3C]  
Sent: Monday, October 30, 2023 8:50 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] UL1007 vs VW-1 Flammability ratings

 

Hello Experts

 

I have a battery box that has wiring to UL1007. I can see that UL1007 has a
vertical flame test requirement.

 

How dose this compare with UL VW-1 ?

 

Regards

 

Steve Clarke

Test Engineer

 

Unit 3 Compliance Ltd

EMC : Electrical Safety : Environmental & Vibration : CE & UKCA :
Consultancy

 

www.unit3compliance.co.uk   |
step...@unit3compliance.co.uk   |
+44(0)1274 911747

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298


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[PSES] Exploding lithium batteries are causing fires in Oregon's landfills

[Richard Nute]

Improper disposal of lithium batteries.

https://www.opb.org/article/2023/10/21/exploding-lithium-batteries-landfill-
fires/?utm_medium=email_campaign=First%20Look%20Oct%2021%202023_cont
ent=First%20Look%20Oct%2021%202023+CID_d001250f39c0737f6bb7b9129f44e9ca_
source=firstlook_term=Learn%20more

"He said he hopes, in the future, "people who put (lithium batteries) into
the marketplace bear some of the responsibility" for the fires."

Here in Deschutes County, Oregon,
https://www.deschutes.org/solidwaste/page/hazardous-waste-management

"Batteries:  Single-use alkaline dry cell batteries (flashlight batteries,
etc) can be disposed of in the regular garbage.  Modern single-use dry cell
batteries are mercury free and do not contain regulated hazardous
constituents."

"Portable rechargeable batteries (NiCad, Lithium ion from tools, cell
phones, cameras, etc) can be recycled at many major tool retailers and
rechargeable device retailer.  They are also accepted at the Hazardous Waste
Facility."

Best regards,
Richard Nute






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[PSES] safety under single fault

[Richard Nute]

Hello from Bend, Oregon:

On September 4, 2022, a plane carrying 10 people crashed into Puget Sound's
Mutiny Bay near Whidbey Island.  The National Transportation Safety Board,
which investigated the crash, said Thursday that a single component of a
critical flight control system failed, causing an unrecoverable,
near-vertical descent.  

"The Mutiny Bay accident is an incredibly painful reminder that a single
point of failure can lead to catastrophe in our skies," NTSB Chair Jennifer
Homendy said in a news release.

Nate Bingham, who is representing the Ludwigs' families, said the plane
crashed because of "an antiquated design with a single point of failure."

Details:
https://apnews.com/article/seaplane-crash-puget-sound-san-juan-island-10-kil
led-531d4e5a2dfed65370294243b1a07157

This incident serves to remind us that in our field of product safety, we
require the product to be safe even in the event of a failure of any single
component.  

Best regards,
Rich

 

Boats from the U.S. Coast Guard and Kitsap County Sheriff's Office search
the area off Whidbey Island north of Seattle on Sept. 5, 2022, where a
chartered floatplane crashed the day before, killing 10 people. Stephen
Brashear/AP file






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Re: [PSES] BBC news article re Li-ion batteries...

[Richard Nute]

 

 

In my career, I investigated (in the USA) a large number of field failures 
(mostly fires) of safety-certified products.  The claims were against us as the 
manufacturer, not the certifier.  The claimant or his insurance would hire an 
investigator to identify the cause of the fire, where one of the causes could 
be our product.  In no incident was the certifier or regulatory authority 
invited to participate in the investigation.  (Invitations were from the loss 
side, and were intended to determine who would pay for the loss.)  I don’t 
recall any incident where our product was proven to be the cause of the fire.  
No incident was caused by ineffective or insufficient safety requirements for 
our products.

 

Our enclosures were usually HB-rated material.  If ignited, the enclosure would 
burn vigorously and thoroughly, tending to mask its ignition source.  Hence, we 
were included as a possible source of the fire.  

 

We (as members of this community) do pretty good at preparing product safety 
requirements and inserting them into standards followed by testing and 
certification.  Governments do (or can do) pretty good at requiring products to 
be certified as a condition of being in the marketplace.   

 

BBC and other news sources (as well as individuals and organizations) can bring 
such product safety certification deficiencies to the attention of governments, 
who must then address requirements for certification.  

 

Forgery is a separate one-on-one issue, and cannot be addressed by traditional 
product safety work.  

 

Best regards,

Rich (in Oregon, USA, where certification of electrical products is required by 
Oregon state law)

 

“Certified electrical product” means an electrical product that is certified 
under ORS 479.760 and that is not decertified.

 

 

From: Scott Xe  
Sent: Saturday, August 5, 2023 9:02 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] BBC news article re Li-ion batteries...

 

Dear Ted,

 

I couldn't agree with your views more.  It is crucial for us to tackle these 
issues, despite the existing regulations and testing standards in place.  The 
regulatory authorities and enforcement bodies must thoroughly assess why these 
measures have proven ineffective in preventing the sale of unsafe products in 
the market.

 

Regards,

 

Scott

 

 

On Fri, 28 Jul 2023 at 20:39, Ted Eckert 
<07cf6ebeab9d-dmarc-requ...@listserv.ieee.org 
 > wrote:

I can give additional background on the reason why these fires have become 
common in New York. A large number of residents of New York City use delivery 
services for goods and food, such as Uber-Eats, DoorDash, and GrubHub. The 
adoption of these delivery services accelerated during the COVID lockdown, and 
it has become a major business in the city. The drivers for these services are 
contractors, not employees, and they get paid based on delivery without 
reimbursement for expenses. Driving a car is expensive, and finding parking is 
very hard. Delivery people who drive cars often lose money because they incur 
too many parking tickets. The delivery people have switched to battery-powered 
electric scooters and bicycles. 

 

These small electric vehicles are optimal for the delivery services since they 
can move around stopped traffic easily, and they can be brought inside the door 
of a building for a delivery, avoiding the risk of parking fines or the vehicle 
getting stolen. However, the batteries will only last for a few hours of use at 
most. The delivery people want the option of using the electric bicycle or 
scooter all day to try to make more money. The common solution is to remove the 
battery that came with the vehicle and replace it with a much larger 
after-market replacement. The delivery services do not pay well, so people look 
for the cheapest option they can find for a large battery. The regulations in 
the United States make it easy to order something online that has undergone no 
safety testing at all. The result is that a battery of dubious quality is 
placed in an electric bicycle by a person with dubious technical skills. No 
effort may have been made to match the charger with the battery. The battery 
may not be provided with the physical protection necessary to avoid damage 
during use. The question isn’t why there are so many fires, but why there 
aren’t more considering the circumstances. 

 

In the United States, there is reasonable indemnification of the test 
laboratories. The test laboratories accredited under the OSHA Nationally 
Recognized Test Laboratory (NRTL) system have a reasonable level of protection. 
If a product carrying one of their certification marks fails, they can be sued, 
but it would be hard for that law suit to make it to court. The test 
laboratories will indicate that they tested samples on a given date and found 
those samples to meet the technical requirements of the standard at that 

Re: [PSES] Woodgate's reply on residential Immunity field strength

[Richard Nute]

 

I'm a product safety engineer.  This discussion is based upon a safety
standard specifying a limit for the accessible electric field strength.

 

Doug Smith said:  

 

"These days we think 10 V/m is dangerous."

See:

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3553569/

 

This article (with scholarly research annotated) essentially says that we
don't know the effects of electric and magnetic fields on the body.  It
cites 0.4 uT (>100 V/m) as a potential limit for children.  Doug goes on to
cite his experience with exposure to 100 times 100 V/m with no ill effects.


 

I wonder how the standards writers came up with limiting field strength when
there is no definitive bodily injury?  Probably BOGSAT.   

 

Best regards,

Rich

 

ps:  Field strength conversion calculator:

 

https://www.compeng.com.au/field-strength-calculator/

 

 


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Re: [PSES] 6dB pad

[Richard Nute]

 

This discussion not only applies to EMI testing, it also applies to 
high-frequency and fast risetime pulse voltage measurements.  A 6 dB (2x 
voltage attenuation) or 10 dB (~3x voltage attenuation) in a 50-ohm system 
which would otherwise be subject to reflections due to impedance 
discontinuities (i.e., which create the VSWR) will give a more accurate voltage 
measurement (which would otherwise be dependent on the length of the cable due 
to VSWR).  The attenuator makes the input impedance look like nearly 50 ohms 
regardless of actual load impedance.  Same for a source impedance that is not 
50 ohms.  

 

I’m not sure that you need a pad at both ends.  If the input to the receiver is 
50 ohms throughout the frequency band, then there are no reflections from the 
receiver end and no VSWR that would distort the measurement.  Arguments?

 

Best regards,

Rich

 

From: Ken Javor  
Sent: Saturday, July 15, 2023 10:15 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] 6dB pad

 

Receiver vswr is specified with 10 dB attenuation because the mixer itself is 
not 50 Ω.

 

Antenna vswr is usually best in the middle of the usable frequency range.  
Worst case at the low end for EMI antennas used down to 30 MHz, because except 
for half-wave dipoles, they are electrically short at and near 30 MHz. Antenna 
vswr is typically stated at the antenna port, without any added attenuation.

 

Putting attenuation at the EMI receiver input takes care of mixer mismatch, and 
padding the antenna takes care at the opposite end. You need a pad at both ends 
to completely control vswr-related uncertainty. 

 

Unfortunately, you often cannot stand the desensitization of all the extra 
attenuation.

 

-- 

Ken Javor

(256) 650-5261

 

From: Paolo Roncone mailto:paoloc...@gmail.com> >
Reply-To: Paolo Roncone mailto:paoloc...@gmail.com> >
Date: Saturday, July 15, 2023 at 10:29 AM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Subject: Re: [PSES] 6dB pad

 

Hi Ken

 

Thanks for your feedback. Why should the VSWR be specified with 10 dB 
attenuation? That would alter (for the better) the specified VSWR itself. I 
checked th

e data sheets of 3 antennas that I'm using (a hybrid bilog, a log-periodic and 
a horn) and in all of them a "typical" VSWR is specified, without any mention 
to a 10dB attenuation.

 

Paolo 

 

On Fri, Jul 14, 2023 at 11:33 PM Ken Javor mailto:ken.ja...@emccompliance.com> > wrote:

Not expressing an opinion, just listing some facts. 

 

Absent any input attenuation, vswr will be higher than manufacturer specifies, 
because the specification is with 10 dB input attenuation (typically). 
Therefore, the use of a 6 dB pad, absent any internal attenuation, will not 
meet the manufacturer’s spec for vswr, and thus your uncertainty budget 
increases.

 

If your ambient source is brush noise, preselection should help with that, once 
you are out of band to it.

 

Band stop filters will help with known transmitters.

 

-- 

Ken Javor

(256) 650-5261

 

From: Paolo Roncone mailto:paoloc...@gmail.com> >
Reply-To: Paolo Roncone mailto:paoloc...@gmail.com> >
Date: Friday, July 14, 2023 at 3:53 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Subject: [PSES] 6dB pad

 

Hi all,


I'm having a discussion with my colleague about the use of a fixed 6dB 
attenuation pad at the input of the EMI receiver for radiated EMI in the range 
30MHz - 6GHz.
The pad I'm using is a Weinschel 6dB N-type 50ohm.
My colleague says the pad is an unnecessary element in the measurement chain, 
because the receiver built-in attenuator (typically with 10dB steps) and proper 
adjustments in the amplitude settings are enough.

The reason I'm using the 6dB pad is that - based on my EMI testing experience, 
the 6dB pad is a good trade-off between the need to avoid receiver overload and 
maintaining a good enough noise floor. 

Without the pad the noise floor is of course lower and everything is fine as 
long as the input levels are low enough. 

But in the majority of the test scenarios I'm working on the input levels are 
not so low and the 6dB pad is just enough to avoid triggering the auto built-in 
10dB attenuation, that kicks in when the receiver attenuation is in auto mode, 
and that is oftentimes an overkill, raising the noise floor too much, 
especially in the 1-6 GHz range.

I have the 6dB pad calibrated for cable loss once a year together with the 
N-cable connecting to the antenna. And also the cable calibrated without the 
pad.


The most typical sources of overload are transient noise generated by motors 
(especially brush DC motors)  and signals from radio modules like 2.4G wi-fi, 
Bluetooth and 5G wi-fi.

In addition to overload protection, the 6dB pad improves the VSWR at the 
cable-receiver interface, as explained in C.J.Paul's EMC Introduction to EMC 
(John Wiley 2nd Ed.) Ch.7.
Based on the above I think that, being a resistive network stabilizing the 
50ohm termination impedance at the receiver end, the 6dB 50ohm pad is 

Re: [PSES] Machine status visual Indicators

[Richard Nute]

 

Go for it!

Rich

 

 

From: Steve Brody  
Sent: Friday, June 23, 2023 11:52 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Machine status visual Indicators

 

Experts, 

  

I have a client who would like to use a single LED capable of multiple colors 
instead of a mutli-lamp light tower that we are used to seeing. 

  

It can produce the required colors in accordance with 60204-1, Table 4. 

  

I have read through 60204-1 (machinery) safety and 61310-1 (requirements for 
visual, acoustic, and tactile signals) and did not find anything that prohibits 
the use of a single LED. 

  

Thoughts? 

  

  

  

Steve Brody 

sgbr...@comcast.net   

C - 603 617 9116 


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[PSES] FW: Regulatory & Standard Updates / Oct 2021

[Richard Nute]

 

Hi Brian:

 

I have found this listing to be useful.  Unfortunately, I don’t know how to 
subscribe.

 

Good luck!

Rich

 

 

From: TÜV Rheinland North America  
Sent: Tuesday, November 30, 2021 8:58 AM
To: ri...@ieee.org
Subject: Regulatory & Standard Updates / Oct 2021

 








If you don't see this e-mail correctly, please click here 

 .


Please have in mind that in case you forward this email, your personal data 
might also be forwarded.

 





 



 

 


 


Regulatory Updates

 

10/2021

 






  

 

 





 


This edition of the newsletter provides you with information about new and 
revised approval procedures in your target markets.

 

Stay up to date!

 

Your Market Access Team from TÜV Rheinland


 

 





Europe, the Middle East and Africa


European Union


Draft Commission Implementing Decision Regarding the Consideration of a New 
Biocidal Product

 

 Learn more  

 →


Detailed Rules for Determining the Weight of Waste Single-use Bottles  

 Learn more  

 →


Further Postponing the Expiry Date of Approval of Creosote for Use in Biocidal 
Products  

 Learn more  

 →


United Kingdom


Approval of Ecodesign for Energy-Related Products and Energy Information 
(Lighting Products) Regulations 2021  

 Learn more  

 →


France


Obligation to Report Product Recalls, Entry in Database Required  

 Learn more  

 →


Banning on Plastic Packaging for Fruit and Vegetables  

Re: [PSES] Tracking standards updates

[Richard Nute]

 

Hi Brian:

 

Here are two suggestions:

 

Nemko "News in Brief" by Trond Sollie

https://www.nemko.com/newsletter-signup?utm_campaign=GL+%7C+News+In+Brief+%7
C+2023

_medium=email&_hsmi=260848842&_hsenc=p2ANqtz-9wg1SKLg3ST3lYTRveyREPMCOsX
59duFm4ykvI1h4BlxMCmJDd1wPbs0VeVrYM0_W6GpdGfdkrBjqi51fuXKs-m00DTw_conten
t=260848842_source=hs_email

 

Intertek:

https://www.intertek.com/regulatory-resources/

 

I suspect there are other similar sources, but they may be hard to find.

 

Good luck!

Rich

 

 

From: Brian Gregory  
Sent: Monday, June 19, 2023 10:21 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Tracking standards updates

 

 

Good afternoon compliance colleagues,

 

Have a curiously open-ended question from a major OEM who's very
process-oriented.

So, I'm gathering ideas on how to track standard updates and changes in
multiple markets (US, EU, etc.).

 

I'm familiar with IAEI for collaborating with NA inspectors on NEC updates,
and know that UL & ETL have various update notice/networks, but have no idea
how to track IEC updates, nor residential code changes for someplace like
the UK.  This is applicable mostly for safety, perhaps a little on EMC.

 

thanks!

 

"Colorado" Brian 
720-450-4933

 


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Re: [PSES] Looking for AI or machine vision related ISO standards for safety

[Richard Nute]

 

Hi David:

 

If you are looking for product safety, I would say that product safety
should be independent of AI, or, indeed, of any software.  

 

However, some new power distribution schemes involve "handshaking" (which is
software controlled) before power can be delivered.  So, before power is
delivered, the hardware and the controlling software must be safe.  And,
when power is delivered, the hardware (at both ends) must be safe.  

 

Good luck, and best regards,

Rich

 

 

From: David Huff  
Sent: Wednesday, June 7, 2023 7:37 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Looking for AI or machine vision related ISO standards for
safety

 

All,

I am working to guide a design that uses Artificial Intelligence and machine
vision thru a certification type process (CE Mark) and I am looking for ISO
or IEC standards or similar related guidance.  My theory is that this is
such new territory very little guidance exists yet.  Are there any
recommendations for international guidance.

 

Thanks,

David

 


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Re: [PSES] PLC password

[Richard Nute]

 

Hi Steve:

 

A possible analogy might be providing a 3-to-2-wire adaptor for your product.  
Clearly, doing so results in a misuse of the product (operating a Class 1 
product without a ground).  Safety standards require the product be safe in the 
event of misuse.  

 

Giving the password to a customer results, in my opinion, in misuse of the 
product, which, according to many safety standards, is a condition which must 
be safe.  

 

Providing a password to one customer means that all customers may get the 
password from the first customer.  Your manufacturer loses control of the 
password and might as well not use a password.  

 

Best regards,

Rich

  

 

From: sgbrody  
Sent: Thursday, June 1, 2023 3:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] PLC password

 

I have been asked if there is a standard, or comments within s standard, that 
discusses giving a customer the password to allow them to reprogram the PLC 
when they remove a device and the light curtain that protected it.

 

I believe, that other than it being a terrible idea, that it would probably 
invalidate any approvals the end product had.

 

The customer is asking for a document that supports my opinion.

 

I dud suggest that we send a service person to do the change, and not give up 
the pw.

 

Thoughts?

 

 

 

Sent from my T-Mobile 5G Device

 

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Re: [PSES] EN/IEC 61010-1 insulation question

[Richard Nute]

 

 

Hi James:

 

On further consideration, the standard’s “NOTE” following 6.7.3.1 is incorrect. 
 When a hi-pot test is done on the primary (mains) circuit, the voltage 
(attenuated) will also appear (where it can) in secondary circuits due to the 
capacitance to the primary circuits.  In other words, the primary circuit 
hi-pot test tests all possible insulations, whether primary or secondary.  

 

Of course, the standard requires hi-pot tests of the secondary circuits 
regardless of my assertion.  

 

Best regards,

Rich

 

 

From: James Pawson (U3C)  
Sent: Tuesday, May 16, 2023 11:08 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG; Richard Nute 
Subject: Re: [PSES] EN/IEC 61010-1 insulation question

 

Thanks Richard! 



 Richard Nute wrote 

 

Hi James:

 

My answers to your questions:

 

1.  Does 6.7.3   apply for the clearance between the secondary 
winding and earth as indicated?

Yes.  

2.  If NO to 1) then what parts should this insulation be between? 
3.  If YES to 1) then:

a.  what is the safety hazard that is being addressed by applying Basic 
insulation values from Table 6 here?

The standard’s assumption is that transient voltages do appear in secondary 
circuits.  See NOTE following 6.7.3.1 <http://6.7.3.1> .  A transient voltage 
can cause a clearance or creepage to fail.  Solid insulation is required to 
have suitable electric strength to withstand the transient voltage. 

b.  Why isn’t this shown on Figure D.1e) as being required?

I assume that the figures are either insulation in general, including 
clearances (air insulation) or just for solid insulation.  

4.  If the working voltage between terminals X and Y in the sketch is less 
than the Hazardous Live thresholds in 6.3.1   then it is be 
permitted to be present on an Acccessible external terminal, correct?

Yes.

5.  Earthing either end of this winding will make 6.7.3   
redundant, correct?

I wouldn’t describe the requirement as “redundant.”  If one end of the winding 
is connected to earth, then clearly the clearance and creepage requirements do 
not apply to that one terminal.  However, the other terminal still must meet 
the clearance and creepage requirement.  

 

The standard seems not clear as to whether clearance (air insulation) is 
considered as insulation or a separate parameter.  

 

Note that the values for creepage distance are based on rated voltage, not 
transient voltage.  This is because failure of a creepage is caused by a 
long-term voltage.  However, physically, a creepage cannot be less than a 
clearance.   

 

Good luck,

Rich

 

 


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Re: [PSES] EN/IEC 61010-1 insulation question

[Richard Nute]

 

Hi James:

 

My answers to your questions:

 

1.  Does 6.7.3 apply for the clearance between the secondary winding and
earth as indicated?

Yes.  

2.  If NO to 1) then what parts should this insulation be between? 
3.  If YES to 1) then:

a.  what is the safety hazard that is being addressed by applying Basic
insulation values from Table 6 here?

The standard's assumption is that transient voltages do appear in secondary
circuits.  See NOTE following 6.7.3.1.  A transient voltage can cause a
clearance or creepage to fail.  Solid insulation is required to have
suitable electric strength to withstand the transient voltage. 

b.  Why isn't this shown on Figure D.1e) as being required?

I assume that the figures are either insulation in general, including
clearances (air insulation) or just for solid insulation.  

4.  If the working voltage between terminals X and Y in the sketch is
less than the Hazardous Live thresholds in 6.3.1 then it is be permitted to
be present on an Acccessible external terminal, correct?

Yes.

5.  Earthing either end of this winding will make 6.7.3 redundant,
correct?

I wouldn't describe the requirement as "redundant."  If one end of the
winding is connected to earth, then clearly the clearance and creepage
requirements do not apply to that one terminal.  However, the other terminal
still must meet the clearance and creepage requirement.  

 

The standard seems not clear as to whether clearance (air insulation) is
considered as insulation or a separate parameter.  

 

Note that the values for creepage distance are based on rated voltage, not
transient voltage.  This is because failure of a creepage is caused by a
long-term voltage.  However, physically, a creepage cannot be less than a
clearance.   

 

Good luck,

Rich

 

 


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Re: [PSES] Compliant needle-flame test material vs V-0 material

[Richard Nute]

 

 

Hi Scott:

 

The answer to your question:  

 

“is it possible the V-0 material does not meet the needle-flame test?”

 

is:  Yes.  See:

 

https://www.caplinq.com/blog/ul-94v-certification-vs-ul-94-vtm-certification_190/

 

Best regards,

Rich

 

 

From: Scott Xe  
Sent: Tuesday, April 18, 2023 6:36 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Compliant needle-flame test material vs V-0 material

 

According to EN 62368-1 : 2020 + A11 : 2020 - Cl 6.4.8.4

 

Smaller distances are allowed provided that the part of the fire enclosure or 
fire barrier within

the required separation distance complies with one of the following:

 

• the fire enclosure or fire barrier meets the needle-flame test 
according to IEC 60695-11-5. Severities are identified in Clause S.2. After the 
test, the fire enclosure or fire barrier material shall not have formed any 
holes that are bigger than allowed in 6.4.8.3.3 or 6.4.8.3.4 as appropriate; or

• the fire enclosure is made of V-0 class material; or

• the fire barrier is made of V-0 class material or VTM-0 class 
material.

 

The test house found that the fire enclosure material could not meet the 
needle-flame test and considered non-compliance.  However, the supplier claims 
that the fire enclosure is made of V-0 material meeting the 2nd requirement.  
Since the verification methods and conditions of needle-flame test and UL 94 
are not identical, is it possible the V-0 material does not meet the 
needle-flame test?

 

Thanks and regards,

 

Scott


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Re: [PSES] Multiple electrical power sources

[Richard Nute]

 

 

Hi Steve:

 

The TV broadcast industry electronic products have used two (redundant) AC 
sources for their products for many years.  You may have some help there.

 

Rich

 

 

From: Steve Brody  
Sent: Thursday, April 6, 2023 1:42 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Multiple electrical power sources

 

A new question. 

 

A client's product is using two independent AC power sources on a product, but 
I can't find anything in 61010-1 60204-1 that provide any guidance on 
compliance. 

 

The obvious is that the sections of the product that are fed from source A or B 
are not interrelated in any way that would create a hazard for for the other 
section, that there be a warning label adjacent to each input that says there 
are multiple AC sources, and that each section has it's own circuit protection 
and disconnect, even if a facility disconnect is used for both. 

 

What am I missing? 

 

Thanks, 

 

 

Steve Brody 

sgbr...@comcast.net   

C - 603 617 9116 

 


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Re: [PSES] Low Voltage connectors called out on CCL

[Richard Nute]

 

Hi Ryan:

 

UL makes some of its money through certifications.  Regardless of product
safety, components, including connectors, are certified; their required use
in end-products justifies the requirement for certification of those
components.  So, this is one of those unwritten requirements.  And, if they
are not certified, you will put the demand back on your supplier, who will
apply to UL (which will result in more certification business). 

 

For example, see https://www.ul.com/services/ul-taiwan-usb-test-lab  This is
for USB connectors and cable, and has little to do with safety (except for
extended power range (EPR) in the USB PD specification).

 

As far as I know, there is no requirement in IEC 62368-1, but there may be
such requirement in UL 62368-1.  As one respondent said, ask to see the
requirement.  

 

Good luck!

Rich

 

 

From: Ryan Jazz  
Sent: Thursday, April 6, 2023 11:09 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Low Voltage connectors called out on CCL

 

Hello Members,

We have an audio amplifier being evaluated by a local NRTL to UL 62368-1 3rd
Edition.

The NRTL is calling out all the low voltage connectors on the rear panel on
the Critical Components list.

For example the XLR and TRS connectors.

*   Can someone please let me know where this requirement could be
coming from?

Traditionally only connectors associated with AC voltages have been called
out on the CCL.

The NRTL will not allow us to use these low voltage connectors if the part
is not UL Recognized.

Is there something in UL 62368-1 3rd Edition that requires UR for low
voltage connectors?

Appreciate any comments.

Sincerely,

Ryan Jazz

Ryan Jayasinghe

Regulatory Compliance Engineer

rjayasin...@line6.com  

 

"After silence, that which best expresses the inexpressible, is music" -
Aldous Huxley

 

LINE6

26580 Agoura Road

Calabasas CA 91302

line6.com

ampeg.com

 

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Re: [PSES] Ferrules

[Richard Nute]

 

 

Hi Steve:

 

More than you need to know about ferrules and UL 508:  
https://www.youtube.com/watch?v=3B09qSLek8Q

 

I suspect that few commercially available ferrules are V-0.  I found ferrules 
that were nylon or vinyl.  Nylon is HB.

 

However, UL certifies ferrules, UL 486F.  Para. 6.3.1 a) specifies HB 
flammability.

 

My suggestion is to subject the assembled ferrules to the UL 94 V- test.  The 
wire insulation is rated VW-1.  The copper wire will heat-sink the ferrule, 
especially if the wire end goes into a terminal.  Assembled, I suspect that an 
HB ferrule will pass the V-0 test, or be close enough.  Not much fuel in a 
ferrule . Chances are that the ferrule will be completely consumed before the 
V-0 test is complete due to the ten 10-second flame applications.  

 

I’ve attached my data sheet for the UL 94 V- tests.  Note that the difference 
between V-1 and V-2 is that V-2 has flaming drops that ignite cotton.  

 

Best regards,

Rich

 

 

From: sgbrody  
Sent: Monday, April 3, 2023 12:46 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Ferrules

 

Hi all,

 

I have a 3rd party who is requiring 94V-0 on the ferrules of a connector.  Up 
to now the ferrules being used have been HB.

 

What say ye, esteemed experts?

 

Opinions, comments welcome.

 

 

 


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UL94d.pdf
Description: Adobe PDF document

Re: [PSES] X-Caps after Diode Bridge

[Richard Nute]

 

Hi Brian:

 

I found these explanations on the web:  
https://www.tecategroup.com/products/capacitors/ac-safety-capacitors.php

 

X Capacitors: Also known as "across-the-line capacitors." Class X safety 
capacitors are used between the "live" wires carrying the incoming AC current. 
These capacitors are used in applications where failure of the capacitor will 
not lead to risk of electrical shock to the user. A capacitor failure in this 
position will usually cause a fuse or circuit breaker to open.

 

Y Capacitors: Also known as "line-to-ground capacitors" (line bypass). Y 
capacitors are used in applications where failure of the capacitor could lead 
to the danger of electrical shock to the user, if the ground connection is lost.

 

Filter caps are on the load (DC output) side of the rectifier.  The pulse 
(charging) current through the capacitors returns to the rectifier, and then to 
the AC line.  While one side of the filter caps is often connected to ground, 
very little pulse current returns to the AC line via the equipment PE wire.  

 

Because the filter caps are not directly across the line, they are not X 
capacitors.

 

Failure of a filter cap is usually mitigated by a fuse in the AC line.  

 

For further information on X (and Y) caps, see IEC 60384-14.  

 

Hope this helps.  Best regards,

Rich

 

 

From: Brian Kunde  
Sent: Monday, April 3, 2023 9:24 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] X-Caps after Diode Bridge

 

We use X2 caps in RF filters prior to the Diode Bridge.  Do filter caps after 
the Diode Bridge (DC), but before the isolation transformer,  have to be X2?  
How about filter caps to Chassis/PE after the Bridge? Do they have to be 
Y-caps?  

 

Thanks,

The Other Brian

 

PS: We typically buy power supplies, so I am not familiar with the downstream 
requirements. 

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[PSES] FW: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan / Midwest Region

[Richard Nute]

 

FYI.

 

From: Roland Gutzky  
Sent: Friday, March 24, 2023 1:32 PM
To: char...@sulisconsultants.com; ri...@ieee.org
Subject: FW: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan 
/ Midwest Region

 

Hi Folks,

 

One of my colleagues passed this thread to me as he follows the server on IEEE.

 

I am the person at Eurofins MET Labs that represents our field evaluation 
service.  Is there some information that I can provide for you (happy to have a 
call to assist)? 

 

Roland Gutzky

Senior Sales Executive

Eurofins Electrical and Electronic Testing NA, Inc.

Telephone: 512-287-2523

roland.gut...@metlabs.com <mailto:roland.gut...@metlabs.com> 

Meet with me: https://calendly.com/rgutzky

 



 

This e-mail including its attachments may contain confidential and proprietary 
information. Any unauthorized disclosure or use of this e-mail including its 
attachments is prohibited and may be prosecuted. If you are not the intended 
recipient, please inform the sender by an e-mail reply and delete the message. 
Transmission by e-mail is not secure and can result in errors or omissions in 
the content of the message. Despite state-of-the-art precautions we cannot 
guarantee that e-mails and attachments are free from viruses. We accept no 
liability for viruses or any transmission-related errors and omissions. You 
need to always virus-check any e-mails and attachments.

Eurofins companies are independent legal entities that are bound only by 
members of their management bodies. No other persons have representation power 
unless specifically authorised by proxy or other legal means.

 

From: Rick Cooper mailto:rick.coo...@metlabs.com> > 
Sent: Thursday, February 23, 2023 12:13 PM
To: Roland Gutzky mailto:roland.gut...@metlabs.com> 
>
Subject: FW: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan 
/ Midwest Region

 

 

From: Richard Nute mailto:ri...@ieee.org> > 
Sent: Thursday, February 23, 2023 13:01
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan 
/ Midwest Region

 

[EXTERNAL EMAIL] DO NOT CLICK links or attachments unless you recognize the 
sender and know the content is safe.

 

 

Hi Charlie:

 

>From my reading of the FEB requirements, I suspect the AHJs have the lists.

 

Best regards,

Rich

 

 

From: Charlie Blackham mailto:char...@sulisconsultants.com> > 
Sent: Thursday, February 23, 2023 12:38 AM
To: ri...@ieee.org <mailto:ri...@ieee.org> ; EMC-PSTC@LISTSERV.IEEE.ORG 
<mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: RE: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan 
/ Midwest Region

 

Rich

 

I’m looking at a similar project myself

 

>The FEB must be acceptable to the AHJ in the region where the equipment is to 
>be installed.

 

Are there published lists anywhere, or is it a case of asking the relevant AHJ?

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Tel: +44 (0)7946 624317

Web: https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 

From: Richard Nute mailto:ri...@ieee.org> > 
Sent: 22 February 2023 23:33
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan 
/ Midwest Region

 

 

Hi Carl:

 

I’m not able to identify candidate FEBs as you requested.  Most NRTLs, small to 
large, also are FEBs.  I only found one accredited FEB who wasn’t an NRTL, SGS 
in Switzerland (a very big company).  

 

Here is a good and complete (straight-forward) explanation of the field 
inspection service in the USA and Canada:

 

https://metlabs.com/services/on-site-field-testing-and-evaluation/field-inspection-frequently-asked-questions/

 

Here is one of the field evaluation body, FEB, accreditation schemes:

 

https://www.iasonline.org/services/field-evaluation-bodies/

 

The FEB must be acceptable to the AHJ in the region where the equipment is to 
be installed.

 

Rich

 

 

 


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Re: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan / Midwest Region

[Richard Nute]

 

 

Hi Charlie:

 

>From my reading of the FEB requirements, I suspect the AHJs have the lists.

 

Best regards,

Rich

 

 

From: Charlie Blackham  
Sent: Thursday, February 23, 2023 12:38 AM
To: ri...@ieee.org; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan 
/ Midwest Region

 

Rich

 

I’m looking at a similar project myself

 

>The FEB must be acceptable to the AHJ in the region where the equipment is to 
>be installed.

 

Are there published lists anywhere, or is it a case of asking the relevant AHJ?

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Tel: +44 (0)7946 624317

Web: https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 

From: Richard Nute mailto:ri...@ieee.org> > 
Sent: 22 February 2023 23:33
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan 
/ Midwest Region

 

 

Hi Carl:

 

I’m not able to identify candidate FEBs as you requested.  Most NRTLs, small to 
large, also are FEBs.  I only found one accredited FEB who wasn’t an NRTL, SGS 
in Switzerland (a very big company).  

 

Here is a good and complete (straight-forward) explanation of the field 
inspection service in the USA and Canada:

 

https://metlabs.com/services/on-site-field-testing-and-evaluation/field-inspection-frequently-asked-questions/

 

Here is one of the field evaluation body, FEB, accreditation schemes:

 

https://www.iasonline.org/services/field-evaluation-bodies/

 

The FEB must be acceptable to the AHJ in the region where the equipment is to 
be installed.

 

Rich

 

 


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Re: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan / Midwest Region

[Richard Nute]

 

Hi Carl:

 

I’m not able to identify candidate FEBs as you requested.  Most NRTLs, small to 
large, also are FEBs.  I only found one accredited FEB who wasn’t an NRTL, SGS 
in Switzerland (a very big company).  

 

Here is a good and complete (straight-forward) explanation of the field 
inspection service in the USA and Canada:

 

https://metlabs.com/services/on-site-field-testing-and-evaluation/field-inspection-frequently-asked-questions/

 

Here is one of the field evaluation body, FEB, accreditation schemes:

 

https://www.iasonline.org/services/field-evaluation-bodies/

 

The FEB must be acceptable to the AHJ in the region where the equipment is to 
be installed.

 

Rich

 

 

From: emcl...@gmail.com  
Sent: Wednesday, February 22, 2023 2:16 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Non-NRTL Field Inspection Service Provider in the Michigan / 
Midwest Region

 

A friend asked me if I could refer him to a field inspection service provider 
for computer/ITE products intended for use within factory environments.  I'm 
aware that the major NRTLs offer this service apart from their NRTL 
accreditation, so I'm asking for other referrals for smaller service providers.

 

The scope is for USA and Canadian installations and this company would like 
that source to provide engineering review of the product in question in advance 
of the inspection, as well as the inspection itself and tag as needed.

 

Thanks in advance,

 

Carl


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Re: [PSES] AC Adaptor - Singapore - Brand Name?

[Richard Nute]

 

 

Hi Ryan:

Designate the model number as your brand name.

Best regards,

Rich

 

From: Ryan Jazz  
Sent: Friday, February 10, 2023 9:34 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] AC Adaptor - Singapore - Brand Name?

 

Hello Members,

We have an AC Adaptor we purchase and rebrand with our model number.

We are renewing our AC Adaptor certificate for Singapore.

We have been told this adaptor is required to display our brand name (logo).

*   If this is indeed a requirement can someone please cite the source?

We would like to use this on two different brands and draw from the same
stock and thus would like to keep them "unbranded".

Thank you,

Ryan Jazz

 

Ryan Jayasinghe

Regulatory Compliance Engineer

rjayasin...@line6.com  

 

"After silence, that which best expresses the inexpressible, is music" -
Aldous Huxley

 

LINE6

26580 Agoura Road

Calabasas CA 91302

818.575.3711

line6.com

ampeg.com

 

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Re: [PSES] Electrical Safety - Fundamental Standards and Concepts

[Richard Nute]

 

 

Hi James:

 

Understanding the basic physics and rationale of the safety standards
requires reverse engineering of the requirements.  And an understanding of
the people (and their biases) that wrote the standard.  Very difficult.

 

And, the safety standards are not necessarily in agreement with each other.
For example, one would think that electric shock requirements are
independent of the type of equipment, but they are not.  (In my opinion, we
should have a safety standard that addresses electric shock rather than
equipment.)

 

60664-1 is largely based on research by Stimper.  60479 is largely based on
research by Biegelmeier.  60990 has a good bibliography, although some of
the references have been ignored.  

 

I would recommend the following sources:

 

"Electrical Product Compliance and Safety Engineering," by Steli
Loznen, Constantin Bolintineau, and Jan Swart.  ISBN 13: 978-1-63081-011-5.

Papers presented at the annual IEEE Product Safety Engineering
Society "International Symposium on Product Compliance Engineering," 2004 to
2022. 

Join one or more national committees addressing product safety
standards.  

IEC Technical Committee documents.

UL "Bulletins of Research."  No longer available from UL, but
may be in some technical libraries.

Articles by Charles Dalziel. 

Books by Dr. Vyto Babrauskas, Ph.D. (Dr. Fire.)

Product Safety Newsletter, Product Safety Engineering
Newsletter.

"Electrical Shock Safety Criteria," Proceedings of the First
International Symposium on Electrical Shock Safety Criteria

1st Edition - January 1, 1985.  Editors: J.E. Bridges, G.L. Ford, I.A.
Sherman.  eBook ISBN: 9781483162201

 

With regard to electrically-caused fire in 62368-1, the PIS requirements
come from 60065 and Ernst Storm (deceased).  The 15-watt requirement came
from me based on ignition tests.  

 

Thermal burns are not due to object temperature, but skin temperature.
Standards requirements are object temperature.  

 

Have fun!  Best wishes for the holiday season,

Rich

 

 

From: James Pawson (U3C)  
Sent: Wednesday, December 7, 2022 5:07 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Electrical Safety - Fundamental Standards and Concepts

 

Hello experts,

 

My goal is to put together a reading and reference list of fundamental
standards that help me understand the basic physics and rationale behind the
requirements in safety standards (mainly EN 62368-1, EN 61010-1, EN
60335-1).

 

I've been finding a lot of useful references from the Normative References
sections of these standards and from the IEC TR 62368-2 explanatory notes.

 

In your opinion, what standards should I add to this list to expand my
knowledge of electrical safety?

 

Thanks in advance

James

 

 

 

General Terminology

  IEC 60050 IEV "Electropedia" although this
is sometimes lacking

 

Electric shock

IEC 60664-1 "Insulation coordination for equipment within low voltage supply
systems - Part 1: Principles, requirements and tests"

IEC 60990-1 "Methods of measurement of touch current and protective
conductor current"

IEC 60479 series shock current on humans and livestock

IEC 61201 Touch voltage limits

 

Electrically caused fire

Power source classification in 62368-1 references IEC 60065 and IEC 60950-1.
But where did they derive their information from? What are the power levels
based on?

UL 94 and UL 1581 for material and cable flammability

 

Thermal Burn

Basic standards detailing risks of touch temperatures ISO 13732-1 and IEC
Guide 117

Other?

 

Radiation

IEC 62471 "Photobiological safety of lamps and lamp systems"

IEC 60065 for audio levels

Other?

 

Mechanical hazards

???

 

 

 

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
Consultancy

 

  www.unit3compliance.co.uk  |
 ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

 


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Re: [PSES] Secondary creepage/clearance

[Richard Nute]

 

 

Hi Steve:

 

Mains circuits are subject to lightning and switching transients both 
line-to-neutral and line/neutral-to-ground.  The transients are normal; to 
prevent insulation breakdown and consequential electric shock, the electric 
strength of mains-to-ground and mains-to-other circuits insulations must exceed 
the expected transient voltages.  (Electric strength requirements based on 
transient voltages are specified in IEC 60664-1, supported by research by 
Stimper.) 

 

The mains transients can be capacitively coupled to secondary circuits, 
depending on the configuration of the isolation scheme.  In most cases, the 
isolation scheme and the impedance of the secondary circuit attenuates the 
transient voltage to near zero. This point seems to be recognized by IEC 
60101-1.

 

Then, as Brian Kunde has said, secondary circuit devices such as relays, 
solenoids, and switching can generate transients in the secondary circuits.  In 
most cases, such transient voltages are small and are attenuated by the 
secondary source impedance. 

 

IEC 60601-1 has a similar requirement, although it includes clearance 
requirements for no-transient secondary circuits.  IEC 62368-1 does not have 
such a requirement.  I wonder what evidence or research supports transient 
voltages in secondary circuits?  

 

Best wishes for the holiday season,

Rich

 

From: Steve Brody  
Sent: Thursday, December 1, 2022 12:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Secondary creepage/clearance

 

I have a client who has a secondary pwb that has traces and vias that may have 
100 vdc on them adjacent to ground.  

 

Per 61010-1 there is a requirement for spacing and/or dielectric test, both 
depending on what the mains voltage is.  

 

The question is why is the mains voltage a consideration or concern if the 
100vdc secondary voltage is several layers of impedance and circuitry from the 
mains?  

 

Is it a concern that a surge on the mains would trickle down to the secondary 
circuit, or is there another reason/rationale?  

 

I suggested that a dielectric test per Table 6 [in A1] would suffice and put 
the issue to rest for this product, but the question from the designers remains 
as to why is it a concern in the standard of what the mains voltage is. 

 

Is there anything in the standard, that I haven't found, that does not require 
Table 6 to be followed if there is no way for a mains surge to impact the 
secondary voltage?  

 

I look to the experts for an explanation.  

 

Thanks, 

 

Steve Brody 

  sgbr...@comcast.net 

C - 603 617 9116 

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Re: [PSES] Pending Regulatory Change to UKCA Program

[Richard Nute]

 

“It’s a fact the CE mark adds way more cost than the return on investment of 
performance improvement.”

 

Reminds me of a marketing manager saying to me that safety (and, I assume, 
safety certification and EMC) do not generate sales.

 

Rich

 


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Re: [PSES] Magnetic fields, human exposure standards, and pacemakers

[Richard Nute]

 

Mains power lines running overhead make magnetic fields at 50/60 hertz….

 

I lived near Barcelona, Spain, for almost two years.  The local trains used 
overhead lines.  The stations used color CRT displays for train info.  You 
could tell when a train was arriving as the display would distort (you couldn’t 
decipher the display) proportional to the current in the overhead line.  When 
the train stopped, the display was normal again.  

 

Rich

 

 


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Re: [PSES] Surge Protection Device required by NEC

[Richard Nute]

 

The NEC 670.6 quote triggers some questions:

 

I wonder why industrial machinery with a safety interlock is required to have 
surge protection as opposed to machinery that does not have an interlock?

 

Is an “on-off” or “run-stop” control considered a “safety interlock”?

 

Is the “surge” a higher-than-normal power-line voltage or is it an impulse from 
switching or lightning?

 

Does “effectively protected” mean passing the dielectric (hi-pot) test?

 

Richard Nute

Bend, Oregon, USA

(Several inches accumulation of snow this morning, but above freezing.)

 

 

From: Doug Powell  
Sent: Tuesday, November 1, 2022 11:28 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Surge Protection Device required by NEC

 

>From the 2020 Edition, emphasis is mine.

 

"670.6 Surge Protection. Industrial machinery with safety interlock control 
devices not effectively protected from voltage surges on the incoming supply 
circuit shall have surge protection installed."

 

It does not say where this protection needs to be applied, so I assume it can 
be within the machine or somewhere in machine supply. Also, does the product 
you are inquiring about fall under the definition of Industrial Machinery, NFPA 
79? 

 

-Doug

 

Douglas E Powell

Laporte, Colorado USA

 <mailto:doug...@gmail.com> doug...@gmail.com

 <https://www.linkedin.com/in/coloradocomplianceguy/> LinkedIn

 

(UTC -06:00) Mountain Time (US-MDT)

 

 

 

On Tue, Nov 1, 2022 at 11:55 AM Brian Kunde mailto:bkundew...@gmail.com> > wrote:

It just came to my attention that section 670.6 of the US National Electric 
Code 2017 requires a listed Surge Protection Device (SPD) to be on any 
Industrial Machine that has an Interlock, or I assume any kind of safety 
function.  Is this true? The only information I can find on the internet is 
from the companies that make and sell the SPDs which can often be very one 
sided.  Is there more to this story that I am missing?

 

Does the Surge Protection have to be listed? Are there specifications for the 
SPD? Is there a Surge Immunity Test that be used to validate and verify whether 
an additional SPD is required or not?  

 

Thanks,

The Other Brian


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Re: [PSES] Confusion about IEC 60601-1-11 Power Cord Requirements and Functional vs Protective Earth Terminals

[Richard Nute]

 

Hi Matthew:

 

According to IEC 60601-1 Sub-clause 6.2:

 

ME EQUIPMENT energized from an external electrical power source shall be
classified as

CLASS I ME EQUIPMENT or CLASS II ME EQUIPMENT

Its okay to have Class I equipment with Class II construction throughout.
However, you are likely to find it unacceptable to authorities to use a
protective earth cord without an internal connection.  I suggest you run a
PE wire from the appliance inlet to the metal tank or some other metal in
the equipment - even though it is not needed as the equipment is
double-insulated throughout.

 

Best regards,

Rich

 

 

 

From: Matthew D. Varas  
Sent: Tuesday, October 18, 2022 9:53 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Confusion about IEC 60601-1-11 Power Cord Requirements and
Functional vs Protective Earth Terminals

 

Hello, 

 

We are converting a product to comply with 60601-1-11 for home use and I was
hoping to get some clarification on the power cord requirements. 

 

The device is a mains-powered heating tank which uses snap-action
thermostats to control mains power through the internal heating pad. It is
currently intended for professional healthcare environments and has a metal
tank that is treated as an applied part. A three-prong power cord is used to
provide a protective earth connection as a MOP which, as I understand it, is
not allowable per clause 6 of 60601-1-11 ("shall be class II or internally
powered" and "shall not have a functional earth terminal"). 

 

The sales and marketing folks do not want to switch to a two-prong cord out
of concern that it will look unprofessional when used in a professional
healthcare environment, regardless of the fact that it will be redesigned to
be double insulated through other MOP's. In trying to respond to them a
coworker and I are in disagreement about how to interpret clause 6 and could
use some help. Does this mean that :

 

1.  The power cord must be two prong, or
2.  The power cord can be three prong but can have the earth terminal
not connected internally

If it were to not be connected internally, I assume that a C18 connector on
the device (while still using the three-prong cord) would be the correct
path, however I interpret this to mean option 1 is correct. 

 

 

Which leads to the second related part of my question: 

I am unclear on the differences between a functional earth terminal and a
protective earth terminal. After looking at Figure 2 in 60601-1, in this
particular application it doesn't seem like there would be a difference
between the two since it uses only mains power. Is this correct and can
someone help me understand what the difference would be between the two,
especially as it relates to home use? 

 

Thank you,

 

Matthew Varas

Electrical Engineer

WR MEDICAL ELECTRONICS CO.

direct  651.604.8473 | cell 763.222.6900

email m...@wrmed.com  

follow wr medical   Twitter
  |
wrmed.com
  

 


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Re: [PSES] Confusion about IEC 60601-1-11 Power Cord Requirements and Functional vs Protective Earth Terminals

[Richard Nute]

 

 

Hi Matthew:

 

In answer to your question how to distinguish between functional earth
circuits and protective earth circuits:

 

Protective earth (PE) circuit carries fault current to earth.  Presumably,
the fault current is from a mains-to-earth fault.

 

Functional earth (FE) circuit does not carry mains fault current to earth.
I think of functional earth circuits as carrying functional signal returns
and functional faults, although they may also be for establishing an
equipotential environment.  

 

PE and FE are usually connected together.  In this case, the sites of the
possible mains-to-earth faults must be identified and the resulting current
path must be identified to determine which conductors are PE and which are
FE.

 

Hope these comments help.

 

Best regards,

Rich

 

 

 

From: Matthew D. Varas  
Sent: Tuesday, October 18, 2022 9:53 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Confusion about IEC 60601-1-11 Power Cord Requirements and
Functional vs Protective Earth Terminals

 

Hello, 

 

We are converting a product to comply with 60601-1-11 for home use and I was
hoping to get some clarification on the power cord requirements. 

 

The device is a mains-powered heating tank which uses snap-action
thermostats to control mains power through the internal heating pad. It is
currently intended for professional healthcare environments and has a metal
tank that is treated as an applied part. A three-prong power cord is used to
provide a protective earth connection as a MOP which, as I understand it, is
not allowable per clause 6 of 60601-1-11 ("shall be class II or internally
powered" and "shall not have a functional earth terminal"). 

 

The sales and marketing folks do not want to switch to a two-prong cord out
of concern that it will look unprofessional when used in a professional
healthcare environment, regardless of the fact that it will be redesigned to
be double insulated through other MOP's. In trying to respond to them a
coworker and I are in disagreement about how to interpret clause 6 and could
use some help. Does this mean that :

 

1.  The power cord must be two prong, or
2.  The power cord can be three prong but can have the earth terminal
not connected internally

If it were to not be connected internally, I assume that a C18 connector on
the device (while still using the three-prong cord) would be the correct
path, however I interpret this to mean option 1 is correct. 

 

 

Which leads to the second related part of my question: 

I am unclear on the differences between a functional earth terminal and a
protective earth terminal. After looking at Figure 2 in 60601-1, in this
particular application it doesn't seem like there would be a difference
between the two since it uses only mains power. Is this correct and can
someone help me understand what the difference would be between the two,
especially as it relates to home use? 

 

Thank you,

 

Matthew Varas

Electrical Engineer

WR MEDICAL ELECTRONICS CO.

direct  651.604.8473 | cell 763.222.6900

email m...@wrmed.com  

follow wr medical   Twitter
  |
wrmed.com
  

 


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Re: [PSES] Assess risk of electric shock from charged capacitors

[Richard Nute]

 

 

Hi Scott:

 

Many dual channel scopes (whether digital or analog) include an “add” function 
for the two channels.  One channel must be inverted to measure the charged 
capacitance.

 

The resistance of the two probes must be accounted for in the capacitance 
discharge time.  (The same – for only one probe -- is true for the scheme using 
an isolating transformer.)

 

You should get the same results for both methods.

 

Best regards,

Rich 

IEEE Life Fellow

IEEE Medal for Environmental and Safety Technologies

 

 

 

From: Scott Xe  
Sent: Monday, October 17, 2022 8:18 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Assess risk of electric shock from charged capacitors

 

In order to judge if there is no risk of electric shock from charged 
capacitors, it is required to measure the voltage across L and N of mains plug 
after the removal of power input.  To avoid grounding loop between test 
equipment and the unit under test, an isolating transformer is strongly 
recommended.  I have learnt another way by using Add Function and two hot 
probes of a dual channel DSO.  Can someone advise which way is more common in 
safety conformity test.  Especially the latter one, I have not tried it yet 
before and appreciate any notes I must take in the measurement.

 

Thanks and regards,

 

Scott


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Re: [PSES] Wearables and UL 62368 vs UL 964 Electrically Heated Bedding

[Richard Nute]

 

 

Hi John:  

 

I assume the power is distributed more-or-less evenly throughout the garment.  
See:

 

https://learn.adafruit.com/experimenting-with-conductive-heater-fabric/what-is-it

 

(Be sure to click on the blue “placement” near the bottom of the page and the 
subsequent pages.)

 

If this describes the way the garment heater works, then the quoted standards 
don’t apply very well. I would need to know a bit more about how the heater 
heats the garment to give you advice.

 

Best regards,

Rich

 

ps:  Nice to see and talk with you at ISPCE!

 

 

From: John Allen  
Sent: Wednesday, October 5, 2022 8:18 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Wearables and UL 62368 vs UL 964 Electrically Heated Bedding

 

Hi,

 

I hope everyone is well and happy .

 

I’m hoping I can get some input on my thinking for a heated garment powered by 
a battery pack.

 

1.  The heater is insulated.
2.  The fabric it is in contact with is combustible.
3.  The circuit is PS2 – 16W
4.  I read UL 62368 Clause 6.4.5.2 as the fabric must not ignite under a 
single fault and it must be UL 94VTM.  Am I correct?

 

Also, in researching other “fabric” products, I found UL 964 Electrically 
Heated Bedding.  Following is a summary of how they manage fabric and heating 
elements – 

 

1.  Sec. 6 Covering of Electrical Parts – All electrical parts shall be 
covered (except the connector attached to the bedding) with a “shell” or other 
fabric with no openings.
2.  The heating element shall not be in direct contact with the shell.  It 
shall be insulated with UL AWM.
3.  There shall not be any sharp edges in contact with the shell.
4.  There is a very elaborate flammability test on the shell.  Wash it in 
special soap, let it dry then flame test it.  It does not seem equivalent to UL 
94 testing.
5.  There’s also an “Ease of Ignition” test with a hot plate.

 

Is UL 62368 missing some requirements in regard to Wearables that are made of 
fabric??

Wearable Technology Standards:

*   Wellness or Non-Medical Wearable: IEC/UL 62368-1

https://www.ul.com/services/wearable-technology-testing-and-certification

 

I would appreciate any input you can provide.

 

Best Regards and Be Safe,

 

John

 

 

John Allen | President & CEO | Product Safety Consulting, Inc.

Your Outsourced Compliance Department®

630-238-0188, Cell: 630-330-3145



  www.productsafetyinc.com

 

 

John Allen | IEEE Product Safety Engineering Society

President 2016-2019, Past President 2020-2021, BoG Director at Large 2020-2023

Chairman – Compliance 101 Technical Committee

IEEE Senior Member

 

Keeping our members informed and educated on Product Safety and Certifications



 

  
https://ewh.ieee.org/soc/pses/index.html

 


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Re: [PSES] List of Common Misuses

[Richard Nute]

 

Misuse is using a product for a use which is not a normal use.  An example is 
using a chair (which is for sitting) as a stool.  Or, using a screwdriver for 
prying.  Or using a hammer for breaking concrete.  Each of these misuses can 
lead to injury.

 

Identifying misuse for a TV, a laptop, or a printer is much harder, if not 
impractical.  

 

Rich

 

 

From: Charlie Blackham  
Sent: Wednesday, October 5, 2022 1:18 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] List of Common Misuses

 

I’m not a lawyer, or from the USA, but in Europe the term “misuse” has been 
discussed in various REDCA (Radio Equipment Directive Compliance Association) 
Meetings with Notified Bodies and The EU Commission, and their view is that 
there’s no such thing as “misuse”, it’s just “use”.

 

Drawing up a list of possible “misuses” is ultimately futile, as where do you 
draw the line – user manuals instructions telling you not to use a telephone in 
the bath morph into statements telling you not to use a PBX in the bath.

 

My suspicion as an Engineer, is that some companies want great long lists of 
“do not do X” in the manual as some form of defence against mitigation by 
Darwin Awards nominees – but then you finish up with a manual so big that no 
one reads it anyway

 

Just my 2p / 2c

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Tel: +44 (0)7946 624317

Web: https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 

From: MIKE SHERMAN mailto:msherma...@comcast.net> > 
Sent: 05 October 2022 19:09
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] List of Common Misuses

 

Brian -- 

 

Good to hear from you! 

 

Re your question, it is not clear who the "they" is who is requesting a list of 
misuses. 

 

>From my working experience, we (on advice of Legal) usually did not try to 
>compile a list of misuses in the operating manual, on the theory that if a 
>creative user found another (dangerous) misuse that was not on our list, they 
>might conclude that it must be safe because it wasn't on our misuse list. We 
>emphasized how to use our equipment correctly, and what the scope of its 
>applications were. 

 

However, we would clearly identify in some warnings what not to do where we 
perceived that to be a foreseeable misuse. 

 

Hope this helps!

Mike Sherman 

Sherman PSC LLC 

On 10/05/2022 1:01 PM Brian Kunde mailto:bkundew...@gmail.com> > wrote: 

 

 

My company manufactures Laboratory Equipment such as analyzers and 
determinators. They are highly specialized equipment, yet have an infinite 
range of uses.   

 

Even though all known residual risks are documented in the Safety Warning 
section of the manual, they will commonly request a list of Misuses.  There are 
no buttons, or settings that can be changed by the User that can cause a 
hazard.  The operational environment is clearly defined. So in most all cases, 
I am not aware of any "Misuse" that can cause a hazard. For some reason, this 
answer is not acceptable.  We are expected to come up with something.   

 

Is there a standard or common list of MisUses that seem to satisfy this 
requirement? 

 

How crazy are we to get with this?, e.g., don't use the 400lb analyzer while 
taking a bath?  Don't use it to mow your lawn?  Common 

 

I used to work for a computer company and I couldn't believe the stupid 
warnings we had to put in the manual.   

 

Thanks to all. 

 

The Other Brian 

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Re: [PSES] High Touch Current and GFCIs

[Richard Nute]

 

 

Hi Brian:

 

“Touch current” is current through the body when it touches two conductors.  By 
convention, touch current is measured through a 2,000-ohm resistor in series 
with the PE conductor.  Touch current only exists if two conductors are 
touched, for example, when the PE is open.  If the current is sufficient, it 
can cause enough L-N imbalance current to trip the GFCI.

 

PE current is measured with an ammeter in series with the PE conductor.  In 
your situation, PE current, not touch current, trips the GFCI (because the PE 
is not open).  

 

An isolation transformer on the load side of a GFCI will provide a return 
current path to the isolation transformer rather than an imbalance of current 
through the GFCI.  (I am assuming the isolation transformer neutral is 
connected to ground).  The GFCI will not see an imbalance between L and N. 

 

Best regards,

Rich

 

From: Brian Kunde  
Sent: Monday, August 29, 2022 5:45 AM
To: ri...@ieee.org
Cc: EMC-PSTC@listserv.ieee.org
Subject: Re: [PSES] High Touch Current and GFCIs

 

If I have EE or a rake of equipment or several pieces of equipment plugged into 
a power strip that has a combined touch current that trips a GFCI, what can be 
done about that?  Will an isolation transformer solve the problem?

 

Thanks,

The Other Brian

 


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Re: [PSES] High Touch Current and GFCIs

[Richard Nute]

 

I wouldn’t describe the phenomenon as “cancellation.”  The touch current is 
always present and must have a path to earth/ground.  

 

The equivalent equipment circuit:

Y1 capacitor L-(line)-to-PE. 

Y2 capacitor N-(neutral)-to-PE.  Capacitor value is 25x Y1 capacitor value.

4.6 volts N-to-(grounded)-PE.

 

In the USA, N is connected to a ground rod at the building service entrance.  
PE is connected to N at the breaker box.  In the building, PE is parallel to N, 
but is a non-current-carrying conductor except in the case of a fault. 

 

The Y1 and Y2 capacitors are in series and comprise a voltage divider to an 
open PE.  Because the Y2 capacitor is 25x the Y1 capacitor, the open-circuit 
voltage at the PE connection is very low compared the line voltage (instead of 
the usual half the line voltage).  

 

Normal condition touch current path is from L to Y1 to PE (open) to a 2,000-ohm 
resistor to ground,  Touch current is calculated using Ohm’s Law from the 
measured voltage across the 2,000-ohm resistor. The 2,000-ohm resistor is (in 
essence) parallel to the Y2 capacitor.  Some of the L-to-Y1 current (not touch 
current!) returns to ground through the Y2-N-ground circuit, depending on the 
parallel network of capacitance reactance and the 2,000-ohm resistor.

 

Reverse polarity (L and N reversed in the supply to the equipment) current path 
is N to Y2 to PE (open) to the 2,000-ohm resistor to ground.  Because Y2 is 25x 
Y1, the touch current is much higher than normal polarity.  As in the normal 
polarity condition, some of the current (very small) returns to ground through 
the Y1 capacitor.  

 

If the Y1 and Y2 capacitors are of equal value, the supply voltage is 120 
volts, and the touch current limit is 0.5 mA, the Y1 and Y2 capacitance 
reactance is 238,000 ohms each. The Y2 capacitance is shunted by the 2,000-ohm 
resistor and can be ignored as the voltage across the Y2 and 2,000-ohm resistor 
is 1 volt.  (The current through the 238,000-ohm reactance is 4.2 microamps.)

 

We have a parallel circuit to ground from the junction of Y1 and Y2 when the PE 
is open and when touch current is being measured.  One circuit to ground is 
through the touch current measuring circuit.  The other circuit to ground (via 
the N) is through the Y2 capacitor. If the Y2 reactance is small, a significant 
N current can be in that path to ground thereby reducing the touch current, not 
a partial cancel of the touch current.

 

Best regards,

Rich

 

 

From: John Woodgate  
Sent: Thursday, August 25, 2022 12:32 PM
To: ri...@ieee.org; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] High Touch Current and GFCIs

 

There is also a question in my mind as to whether there can be partial 
cancellation of touch current. I suspect this is highly improbable in the US, 
due to the distribution system ensuring that the neutral has a very low voltage 
difference from the PEC. But in Europe, it's not inconceivable that the neutral 
could be, say, 4.6 V relative to PEC and the neutral-to-PEC capacitance 25 
times that of L to PEC, so that half the L-to-PEC leakage current is cancelled 
by the N to PEC current.

==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk <http://www.woodjohn.uk> 
Rayleigh, Essex UK
It all depends




On 2022-08-25 19:12, Richard Nute wrote:

 

 

I wish to make two points:

 

1.  Kirchoff’s Current Law states that the sum of currents entering a node 
equals the sum of currents leaving the node.  The Law applies to summation of 
leakage (touch) currents (e.g., through a 2,000-ohm resistor) and to summation 
of protective conductor currents (through 0 ohms).  In a power strip protective 
grounding conductor, I’m assuming 0 ohms to ground, so the current is slightly 
higher (1 to 10 % depending on the leakage current limit and the voltage you 
are using) in the protective grounding conductor than leakage (touch) current. 

 

See IEC 60990 for touch (leakage) current and protective conductor current 
measurement procedures.  

 

2.  A GFCI measures the current difference between line and neutral 
conductors, not current in the protective conductor.  It nominally operates at 
5 mA.  We assume (with a reasonable degree of accuracy) that leakage (touch) 
current is 100% of the differential current measured by the GFCI.  It is 
possible, although unlikely, for some of the GFCI differential current to find 
another return path than the protective grounding conductor.

Best regards,

Rich

 

 

From: Lfresearch Jose  
<mailto:00734758d943-dmarc-requ...@listserv.ieee.org> 
<00734758d943-dmarc-requ...@listserv.ieee.org> 
Sent: Wednesday, August 24, 2022 1:44 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] High Touch Current and GFCIs

 

I have wondered about something similar.

 

If I use a 6 way power strip, I’m 

Re: [PSES] High Touch Current and GFCIs

[Richard Nute]

 

 

I wish to make two points:

 

1.  Kirchoff’s Current Law states that the sum of currents entering a node 
equals the sum of currents leaving the node.  The Law applies to summation of 
leakage (touch) currents (e.g., through a 2,000-ohm resistor) and to summation 
of protective conductor currents (through 0 ohms).  In a power strip protective 
grounding conductor, I’m assuming 0 ohms to ground, so the current is slightly 
higher (1 to 10 % depending on the leakage current limit and the voltage you 
are using) in the protective grounding conductor than leakage (touch) current. 

 

See IEC 60990 for touch (leakage) current and protective conductor current 
measurement procedures.  

 

2.  A GFCI measures the current difference between line and neutral 
conductors, not current in the protective conductor.  It nominally operates at 
5 mA.  We assume (with a reasonable degree of accuracy) that leakage (touch) 
current is 100% of the differential current measured by the GFCI.  It is 
possible, although unlikely, for some of the GFCI differential current to find 
another return path than the protective grounding conductor.

Best regards,

Rich

 

 

From: Lfresearch Jose <00734758d943-dmarc-requ...@listserv.ieee.org> 
Sent: Wednesday, August 24, 2022 1:44 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] High Touch Current and GFCIs

 

I have wondered about something similar.

 

If I use a 6 way power strip, I’m assuming all the leakage currents for 
anything plugged in sum. Is that correct? I recall getting a few trips when I 
used a power strip and It’s only just twigged that might be why.

 

Cheers,

 

Derek.

Sent from my iPad





On Aug 24, 2022, at 3:27 PM, Brian Kunde mailto:bkundew...@gmail.com> > wrote:



If I have a rake of electrical equipment with a single power cord and a 
combined touch current exceeding 6mA, and I plug the rake into a circuit with a 
GFCI, will it trip?  

 

Thanks.

 

The Other Brian

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Re: [PSES] Leakage Current Testing (Touch Current) Reference

[Richard Nute]

 

Hi Brian:

 

1.  IEC 61010-1 references IEC 60990 for leakage current tests.  The test 
you describe (MD connected to L1) is NOT in 60990.

 

2.  The PE and N (“grounded” conductor) are connected together at the 
electrical service entrance to the building and connected to a ground rod.  
This means the N is “accessible” because ground is accessible. 

 

3.  When the MD is connected to the chassis and to L1, the indicated 
leakage current should be zero, or near zero.  This is not a useful test.  
(Maybe the lab is using an isolating transformer with an ungrounded output to 
supply the EUT; if this is the case, then the L1 and N leakage current 
measurements are valid although not in compliance with 60990.)

 

I hope these comments answer your questions.  (You should ask the lab to 
measure leakage current in accordance with 60990!)

 

Best regards,

Rich

 

From: Brian Kunde  
Sent: Wednesday, July 20, 2022 10:49 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Leakage Current Testing (Touch Current) Reference

 

This has always confused me.  Consider the EUT as ITE or Laboratory Equipment 
(61010-1).  

 

I can see where the PE conductor is opened and you place the Human Body 
Impedance Circuit (Measuring Device or MD) between the accessible metal chassis 
of the EUT and PE to measure the leakage current that a person might be exposed 
to.  

 

However, when Leakage Current is tested and recorded in the lab, the PE 
conductor is opened, but the MD is placed between L1 and chassis, and then to 
Neutral (L2) and chassis. These values are measured and recorded with the power 
switch  ON and OFF.But in real life, the USER does not have access to L1 or 
N. So why is the test done that way?   

 

Or am I totally mistaken about how the MD is referenced during the test?

 

Thanks to all in advance.

 

The Other Brian


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Re: [PSES] UK plug adaptors with fuse?

[Richard Nute]

 

 

Travel adapters are rarely certified.  The problem is that the plug must comply 
with a country national standard, while the receptacle must comply with a 
different country national standard.  A certification house (or manufacturer) 
rarely is qualified for certifying a plug or receptacle to a country national 
standard different than its local country.

 

The UK power distribution system is a “ring” system.  As such, the plug must 
contain fuses to protect the local load.  An adapter should be fused.  Whether 
the fuse is IEC 5x20 mm, BS1363, or BS643 is inconsequential as the adapter is 
not likely to be certified.  The fuse is for safety, not certification, so any 
fuse (with the correct rating) should be acceptable to you.

 

Many of us don’t have this adapter problem as we use detachable cords.  The 
cord we provide has the correct country plug on the cord.  

 

Best regards,

Rich

 

 

From: MIKE SHERMAN  
Sent: Wednesday, April 27, 2022 12:21 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] UK plug adaptors with fuse?

 

I've used Power Connections products for years: 

https://www.powerconnections.co.uk/ 

They may have something for you, or might be able to point you in the right 
direction. 

 

There seem to be endless unapproved "travel adaptors" available, but relatively 
few seem to have any certifications. What is an acceptable occasional risk for 
a tourist may not be an acceptable risk for a manufacturer to ship with their 
product. 

 

As I recall, the Swiss also have a specific certification standard they require 
for plug adaptors. The Swiss regulators have been very helpful to me in the 
past in understanding these requirements. 

 

Mike Sherman 

Sherman PSC LLC 

On 04/27/2022 6:46 AM Kim Boll Jensen 
<199f0011b1e3-dmarc-requ...@listserv.ieee.org 
 > wrote: 

 

 

Hi 

 

We have been checking several travel adopters for importers here in EU, but we 
have to fail nearly all of them. 

 

One big issue is the UK plug. As I understand they shall comply with BS 1363-3. 
And in this standard §12.4 e) there is a requirement for BS 1363 or BS 643 
fuses. 

 

Some adapters have an 5x20 IEC fuse some have thermo fuses and many have no 
fuse at all. 

 

Do I overlook some exceptions or new requirements, that allows adaptors without 
BS fuse, or are they all just "normal" Asian low quality? 

 

Med venlig hilsen / Best regards, 

Kim Boll Jensen 
Bolls Aps 
22 99 69 91 


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Re: [PSES] Trouble with IEEE Xplore

[Richard Nute]

 

What happens is that I sign in, find the paper, click on 'PDF', putting the 
paper in my cart, then I click on the 'Purchase' tab. That takes me back to the 
sign-in page and empties the cart.

Does anyone else have this problem?

Yes!  Exactly.  I’ve never been able to obtain a paper.  

Best regards,

Rich

 

 

 


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Re: [PSES] [EXTERNAL] Re: [PSES] Protective Earth Terminal-Protective Bonding terminal -interpretation

[Richard Nute]

 

 

Hi Ryan:

 

I want to make several points.  

 

First.  In Europe, a circle around a symbol means the symbol is an
imperative; it must (or is permitted to) be done.  (A diagonal line through
the circle is a negative imperative; it must not be done.)  For example, a
letter "P" in a circle means parking is permitted, while a diagonal line
through the same symbol means parking is not permitted.  A terminal with
adjacent earth symbol in a circle means this terminal must be connected to
earth.  Commonly, an IEC 60320 appliance coupler has the mark adjacent to
the protective earthing conductor terminal.  The connection to earth is
through the power cord protective earthing conductor.  However, the marking
(which is on the inside of the appliance coupler) is not accessible
(visible) to the end user of the equipment; he simply connects the power
cord with protective earthing conductor to the equipment via the appliance
coupler without knowledge of the imperative marking.  

 

Second.  The protective bonding circuit must be connected to the protective
earthing terminal.  Though not stated explicitly, sub-clause 5.6.2.1 and
5.4.2.3.3 (first dashed paragraph) imply this requirement.  

 

Third.  Note that the standard implies that the equipment can have more than
one protective earthing terminal.  See 3.3.11.12 and 5.4.2.3.3 ". main
protective earthing terminal." 5.6.5.1 ".the earthing terminal in the
appliance inlet is regarded as the main protective earthing terminal."
5.7.8 ". a terminal for the protective earthing conductor." Many other
places in the standard use the phrase "a main protective earthing terminal."
All protective earthing terminals must include the protective earthing
symbol marking.

 

Fourth.  F.3.6.1.2:  ". a terminal for bonding wiring from the appliance
inlet already marked with the symbol , IEC 60417-5019 (2006-08), is
acceptable as identification of a protective bonding conductor terminal."
I'm not sure what this means.  Maybe you can use it.

 

Fifth.  These are all internal markings.  As such, they are only useful to
someone who has access to the inside of the equipment and is servicing the
protective conductor system.  Regardless of internal markings, the equipment
is safe for the end user even though non-compliance with the standard. 

 

Sixth.  Protective earthing conductors and protective bonding conductors
have the same insulation color - green-yellow (5.6.2.2).  This means that
either end of a green-yellow conductor is (or can be) a protective earthing
terminal.  An unmarked terminal (of a green-yellow conductor) is a
protective bonding terminal, and a marked terminal is a protective earthing
terminal.  (Presumably, a conductor of any other color connected to either a
protective bonding terminal or to a protective earthing terminal is a
functional earthing conductor.) 

 

I hope you find these comments useful in formulating an argument with your
certification houses.  Good luck.

 

Best regards,

Rich

 


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[PSES] Medical Device Leakage Current Production Line Test Setup

[Richard Nute]

 

 

 

Hi Gary:

 

The measurement of "leakage current" (or "touch current") in the protective
earthing conductor simulates the human body in series with the protective
earthing conductor.  Supposedly, it is a measure of the human body reaction
to the current magnitude.

 

However, if the "leakage current" is less than the limit value, the
equipment is deemed acceptable.  And vice-versa.  

 

So, my question is: Is the measurement of "leakage current" a measure of 

*   human reaction to the current, or 
*   an equipment parameter?

 

 

Best regards,

Rich

 

 

 

From: 05big...@gmail.com   <05big...@gmail.com
 > 
Sent: Wednesday, March 16, 2022 11:23 PM
To: ri...@ieee.org  ; EMC-PSTC@LISTSERV.IEEE.ORG
 
Subject: RE: [PSES] Medical Device Leakage Current Production Line Test
Setup

 

Hi Rich,

Your comments remind me that I prefer to take each step in an analysis with
my "closest to the pin" estimate, and afterwards if I want to be
conservative, apply some overall discounting factor.  The alternative method
of taking a conservative estimate for each step may lead to unrealistic and
non-transparent results.

 

Cheers,

Gary Tornquist

 


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[PSES] Medical Device Leakage Current Production Line Test Setup

[Richard Nute]

 

 

Hi Gary:

 

The measurement of "leakage current" (or "touch current") in the protective
earthing conductor simulates the human body in series with the protective
earthing conductor.  Supposedly, it is a measure of the human body reaction
to the current magnitude.

 

However, if the "leakage current" is less than the limit value, the
equipment is deemed acceptable.  And vice-versa.  

 

So, my question is: Is the measurement of "leakage current" a measure of 

*   human reaction to the current, or 
*   an equipment parameter?

 

 

Best regards,

Rich

 

 

 

From: 05big...@gmail.com   <05big...@gmail.com
 > 
Sent: Wednesday, March 16, 2022 11:23 PM
To: ri...@ieee.org  ; EMC-PSTC@LISTSERV.IEEE.ORG
 
Subject: RE: [PSES] Medical Device Leakage Current Production Line Test
Setup

 

Hi Rich,

Your comments remind me that I prefer to take each step in an analysis with
my "closest to the pin" estimate, and afterwards if I want to be
conservative, apply some overall discounting factor.  The alternative method
of taking a conservative estimate for each step may lead to unrealistic and
non-transparent results.

 

Cheers,

Gary Tornquist

 


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Re: [PSES] Medical Device Leakage Current Production Line Test Setup

[Richard Nute]

 

 

Hi Gary:

 

The measurement of "leakage current" (or "touch current") in the protective
earthing conductor simulates the human body in series with the protective
earthing conductor.  Supposedly, it is a measure of the human body reaction
to the current magnitude.

 

However, if the "leakage current" is less than the limit value, the
equipment is deemed acceptable.  And vice-versa.  

 

So, my question is: Is the measurement of "leakage current" a measure of 

*   human reaction to the current, or 
*   an equipment parameter?

 

 

Best regards,

Rich

 

 

 

From: 05big...@gmail.com <05big...@gmail.com> 
Sent: Wednesday, March 16, 2022 11:23 PM
To: ri...@ieee.org; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] Medical Device Leakage Current Production Line Test
Setup

 

Hi Rich,

Your comments remind me that I prefer to take each step in an analysis with
my "closest to the pin" estimate, and afterwards if I want to be
conservative, apply some overall discounting factor.  The alternative method
of taking a conservative estimate for each step may lead to unrealistic and
non-transparent results.

 

Cheers,

Gary Tornquist

 


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Re: [PSES] Medical Device Leakage Current Production Line Test Setup

[Richard Nute]

 

 

Comments by Savino Macias and Boštjan Glavič triggered some thoughts about
EARTH LEAKAGE CURRENT (IEC 60601-1 defined term) and measurement schemes.  

 

1.  EARTH LEAKAGE CURRENT in IEC 60601-1 (and most other safety
standards) is the current in the protective earthing conductor from the
equipment to the neutral conductor of the mains supply.  
2.  The transformer T1 in Figure 13 is a variable transformer (or
equivalent source) to get 110% of the equipment highest rated voltage. 
3.  The transformer (or source) need not be isolated from the mains as
the point of connection of the leakage current meter, MD, is to the neutral
conductor.  Note that the circuit in Figure 13 has one pole of the
transformer connected to ground (making that pole the neutral conductor).
However, the ground is not in the measurement circuit, but the ground may be
important to protect measurement personnel. 
4.  The MD (Figure 12) measures the voltage across a 1 k-ohm resistor.
Other standards measure the voltage across a 2 k-ohm resistor.  The measured
EARTH LEAKAGE CURRENT in IEC 60601-1 is slightly higher than other safety
standards (e.g., those that cite IEC 60990).  
5.  Supposedly, the resistor values of 1 k-ohm and 2 k-ohm represent the
body resistance at 50 to 60 Hz.  Inserting a real body in place of the MD
will result in 10% or less of the measured leakage current.  
6.  EARTH LEAKAGE CURRENT in IEC 60601-1 (and most other safety
standards) presumes an open ground (fault) in the installation mains supply,
not in the equipment.  However, the equipment power cord or plug may get
damaged so as to open the equipment ground connection to the installation
ground.  (This is common in North America.)
7.  I've often wondered why we measure EARTH LEAKAGE CURRENT with a
simulated body when we're characterizing the equipment.  The difference
between the IEC 60990 leakage current measurement circuit and an ordinary
ammeter is at most a 5% pessimistic difference (and even less using the IEC
60601-1 measurement circuit).  

 

Best regards,

Rich

 

 

From: Boštjan Glavič  
Sent: Thursday, March 10, 2022 9:38 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Medical Device Leakage Current Production Line Test
Setup

 

Dear Savino

 

Please check specs of your AC programmable source if output is isolated
(floating) . Normally it is not. Therefore additional isolation transformer
is needed. 

 

Best regards 

Bostjan 

SIQ Ljubljana

 

Get Outlook za Android   

 

  _  

Od: Savino Macias mailto:smac...@cvi.canon.com> >
Poslano: sreda, 9. marec 2022 21:33
Za: EMC-PSTC@LISTSERV.IEEE.ORG 
mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Zadeva: [PSES] Medical Device Leakage Current Production Line Test Setup

 

Is anyone familiar with the test setup for doing Leakage Current tests? 

I have a device with input voltage of 100-240V, so my production line test
needs to be done at 264V (110% of highest rated voltage).

Would I use a programmable AC power supply to do this test (along with the
leakage test equipment, of course)?

Also, an isolation transformer is required per the 60601-1 standard. Would a
programmable AC power supply act as the isolation or would an isolation
transformer still be needed?

 

Thanks,

Savino Macias

Canon Virginia Inc.


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Re: [PSES] Fuse designations

[Richard Nute]

 

 

Here is some info:

 

https://www.swe-check.com.au/pages/learn_fuse_markings.php

https://www.littelfuse.com/~/media/files/littelfuse/technical-resources/documents/reference-documents/littelfuse_5x20mm-iec-fuse-cap-marking_guide.pdf

 

Rich

 

 

 

From: Brian Kunde  
Sent: Wednesday, March 2, 2022 1:08 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Fuse designations

 

I do not know where the information I have originally came from, but I got this 
and have been using this for over 30 years:

 

FF = Very Fast Acting

F = Fast Acting (Common)

M = Medium Time Lag

T = Time Lag (Common)

TT = Long Time Lag

 

I got this from Bud Lang who was our Safety Guru at Heath Kit many years ago.  

 

The Other Brian

 

On Tue, Mar 1, 2022 at 5:33 PM Douglas E Powell mailto:doug...@gmail.com> > wrote:

All,

 

Over the years, I've seen various ways people include a caution or warning, in 
their user documents or product labels, for replacement fuses. Similar to: 
"replace only with same type and rating of fuse";  followed by a code: 
T1.6AH250V. And for those who may not understand the code, they may sometimes 
add in parentheses some variant of "(1.6 Amp time-lag, ~250V, high breaking 
capacity)". 


So now to my question, US manufacturers sometimes use the phrase "SLO-BLO" or 
"Slow Blow" instead of Time-Lag or Time-Delay.  Are these terms commonly used 
internationally and if so, are they clearly understood?

 

I took some time to look up SLO-BLO and found it's a registered trademark for 
Littelfuse going back to 1957, and it has been continuously renewed since that 
time.


Incidentally, a German Engineer once told me the way he would designate a fuse 
type for a variety of tripping characteristics was in this order from very slow 
to very fast: TT1.0A250V, T1.0A250V, 1.0A250V, F1.0A250V, FF1.0A250V.

 

Thanks, -Doug

 

 

Douglas E Powell

Laporte, Colorado USA

 

(UTC -07:00) Mountain Time (US-MST)

 






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Re: [PSES] Risk assessment versus HBSE

[Richard Nute]

 

 

Hi Doug:  

 

See:

 

https://www.tandfonline.com/doi/pdf/10.1080/01446193.2016.1274418?needAccess=true

 

Best regards,

Rich 

 

 

From: Douglas Nix  
Sent: Wednesday, February 23, 2022 8:57 AM
To: Richard Nute 
Cc: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Risk assessment versus HBSE

 

Hi Rich,

 

Your points are well taken.

 

There are some good ISO standards that relate to exposure to hot and cold 
temperatures. These standards take the type of material, and therefore the 
transfer rate, of heat into account and are quite useful IMO.

 

You are right about the HBSE model, and I think that we need both approaches, 
that is HBSE and “conventional” risk assessment. The issue is always this: what 
do you do when you don’t have any data? Practitioners must start with what they 
know, and that usually means starting with qualitative risk assessments. This 
is especially true in the broader OHS sector where these types of assessments 
are used for workplace inspections. The problem is that when we attach 
arbitrary numeric values to qualitative scales people start to believe that the 
math is somehow “right” regardless of how arbitrary in the input data. Even if 
the math is correct, GIGO. This is what plagues the application of conventional 
risk assessment techniques and why Cox, Quintino and others have been raising 
the alarm for so many years.

 

We’re now in a place where the EU has a semi-quantitative (yes I hate that term 
too, but it’s descriptive) risk assessment tool built into the RAPEX directive 
for use on consumer products and white goods. This same tool has been adopted 
by the US CPSC, although they are not making this widely known. Health Canada 
has their own methodology for the same purpose, and I’m quite sure that if we 
were to examine the methods used by the national health and safety agencies in 
any country that has such an entity, we would find that they too have some 
method like the RAPEX/CPSC or Health Canada methods. So, for now we are stuck 
with what we have. At least we are getting manufacturers to think about risk, 
rather than “just” hazards.

 

Progress comes slowly…

 

--

Doug Nix

d...@mac.com <mailto:d...@mac.com> 

(519) 729-5704

 

"Opportunity is missed by most people because it is dressed in overalls and 
looks like work." - Thomas A. Edison





On 22-Feb-22, at 19:03, Richard Nute mailto:ri...@ieee.org> > 
wrote:

 

 

 

Hi Doug:

 

Thanks for your comments.

 

What bothers me about risk assessment is that the committees that have written 
the standards requiring risk assessment have not critically evaluated the risk 
assessment process.  If they had done so, we would not have the process as we 
know it today.  

 

Actually, I do not fully agree with the Gibson finding that energy causes 
injury.  I can show that the injury parameter is energy per unit time, e.g., 
joules/second.  The body can absorb energy slowly without injury, but not 
quickly.  Consider that a car with people in it can brake or stop without 
causing injury to the passengers, but cannot “crash” to a stop where injury is 
likely.  In both cases, the kinetic energy to stop is the same, but the kinetic 
energy per time to stop is low in braking, but high in crashing.  

 

The attached picture is that of catching three objects and assumes the 
deceleration time is the same for each object.  Note that when we catch an 
object, we can catch it “slowly” and distribute the energy over a longer time 
than catching it “directly.”  I submit this as proof that energy per unit time 
is the parameter that causes injury.

 

HBSE does indeed have (or can have) energy criteria for each form of energy.  
However, I agree that some energy data is not readily available and must be 
researched.  And, using the energy model can be quite complex.  For example, 
injury from thermal energy is often simply taken as accessible temperature, 
sometimes including a time of contact.  Using a single parameter, temperature, 
or including time of contact parameter, does not address the difference between 
an aluminum block and aluminum foil (which is the issue some members of IEC 
TC108/HBSDT are addressing).   Or the difference between an aluminum block and 
a plastic block. 

 

Best regards,

Rich

 

 

 

From: Douglas Nix mailto:d...@mac.com> > 
Sent: Monday, February 14, 2022 12:46 PM
To: Richard Nute mailto:ri...@ieee.org> >
Cc: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Risk assessment versus HBSE

 

Hi Rich,

 

I have to admit that I’ve been thinking about your reply all weekend.

 

As you know, I teach machinery risk assessment and consult in this area 
regularly. I want to stipulate that there are some significant issues with risk 
assessment the way it is most commonly applied in industry, see my list of 
references on this topic at the end of my message. 

 

The inherent subjectivity of ris

Re: [PSES] Numbers of insulation layers in transformer (IEC62368)

[Richard Nute]

 

Hi Joe:

 

Isn't it also true that if the secondary has no accessible conductive parts,
and the entire enclosure meets the requirements for reinforced insulation,
then no safety insulation at all is required in the transformer?  In this
case, wouldn't  the entire contents of the enclosure would be treated as
though they are 230 Vrms AC mains.

 

Yes!

 

Thanks for describing this alternative.  In this case, the transformer has
one layer of tape which is functional insulation.  Or none, in which case
the transformer is an auto-transformer. 

 

Best regards,

Rich  

 

 

From: Joe Randolph  
Sent: Wednesday, February 16, 2022 2:22 PM
To: ri...@ieee.org; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] Numbers of insulation layers in transformer (IEC62368)

 

Hi Rich:

 

You said the following:

 

If the secondary has no accessible conductive parts, then the insulation
between the secondary and accessible surfaces (whether or not conductive) is
"supplementary insulation":  transformer can have one insulation layer,
basic.  (This is uncommon construction and will likely be not acceptable to
many certification houses.)  

 

Isn't it also true that if the secondary has no accessible conductive parts,
and the entire enclosure meets the requirements for reinforced insulation,
then no safety insulation at all is required in the transformer?  In this
case, wouldn't  the entire contents of the enclosure would be treated as
though they are 230 Vrms AC mains.

 

I realize that this might seem like an unlikely type of product, but I have
seen such configurations used in the past, it seemed okay to me.

 

Joe Randolph

Telecom Design Consultant

Randolph Telecom, Inc.

781-721-2848 (USA)

j...@randolph-telecom.com <mailto:j...@randolph-telecom.com> 

http://www.randolph-telecom.com

 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Wednesday, February 16, 2022 5:09 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Numbers of insulation layers in transformer (IEC62368)

 

 

 

Hi Amund:

 

Since the unit does not have grounding/earthing, it is therefore
double-insulated with respect to the input 230 volts (and must bear the
double-insulated symbol).  

 

This requires all accessible conductive parts and accessible surfaces to be
double-insulated from the 230 volts.  

 

If the secondary circuit has any accessible conductive parts (e.g., metal
antenna), then the secondary must be double-insulated from the 230 volts:
transformer must have two insulation layers, basic and supplementary. (This
is the most common construction.) 

 

If the secondary has no accessible conductive parts, then the insulation
between the secondary and accessible surfaces (whether or not conductive) is
"supplementary insulation":  transformer can have one insulation layer,
basic.  (This is uncommon construction and will likely be not acceptable to
many certification houses.)  

 

Good luck, and best regards,

Rich

 

 

From: Amund Westin mailto:am...@westin-emission.no> > 
Sent: Wednesday, February 16, 2022 1:02 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] Numbers of insulation layers in transformer (IEC62368)

 

Do I need one or two insulation layers (tape) between the primary and
secondary windings?

Can find an absolute answer in the standard IEC62368.

 

 

Product:

Input 230VAC

Secondary 24VDC for other Low volt circuits 

No grounding /earthing

No cable outputs

Plastic enclosure

Radio HUB product 

 

Thanks.

 

Best regards

Amund

 

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Re: [PSES] Numbers of insulation layers in transformer (IEC62368)

[Richard Nute]

 

 

Hi Amund:

 

Since the unit does not have grounding/earthing, it is therefore
double-insulated with respect to the input 230 volts (and must bear the
double-insulated symbol).  

 

This requires all accessible conductive parts and accessible surfaces to be
double-insulated from the 230 volts.  

 

If the secondary circuit has any accessible conductive parts (e.g., metal
antenna), then the secondary must be double-insulated from the 230 volts:
transformer must have two insulation layers, basic and supplementary. (This
is the most common construction.) 

 

If the secondary has no accessible conductive parts, then the insulation
between the secondary and accessible surfaces (whether or not conductive) is
"supplementary insulation":  transformer can have one insulation layer,
basic.  (This is uncommon construction and will likely be not acceptable to
many certification houses.)  

 

Good luck, and best regards,

Rich

 

 

From: Amund Westin  
Sent: Wednesday, February 16, 2022 1:02 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Numbers of insulation layers in transformer (IEC62368)

 

Do I need one or two insulation layers (tape) between the primary and
secondary windings?

Can find an absolute answer in the standard IEC62368.

 

 

Product:

Input 230VAC

Secondary 24VDC for other Low volt circuits 

No grounding /earthing

No cable outputs

Plastic enclosure

Radio HUB product 

 

Thanks.

 

Best regards

Amund

 


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Re: [PSES] Earthing -- Star vs Spring/Split Washers

[Richard Nute]

 

Hello James:

 

As for resistance of the connection, I doubt that there is significant
difference.  I have tested both with a high-current-sourcing milliohmeter.
You can repeat the test and see if there is a difference in the resistance.
(Even a loose connection will still pass the high current test.)

 

A star washer is more likely to penetrate paint.  However, a stud mounted in
a panel is independent of paint.  So, a lockwasher simply locks the nut to
the stud and has little to no effect on the resistance of the connection.  

 

Best regards,

Rich

 

 

 

From: James Pawson (U3C)  
Sent: Tuesday, February 15, 2022 7:34 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Earthing -- Star vs Spring/Split Washers

 

Hello all,

 

I've given myself a regular internet headache trying to understand the
relative merits of spring vs star washers for use on an earth stud for
protective earthing purposes.

 

What is the conventional wisdom and justification? I know I can trust you
folks to be above a simple "we've always done it this way"

 

Can anyone point me towards any citable references or standards covering
this subject?

 

I promise I will write a blog post to pull the information together for
future confused generations.

 

Thanks and all the best,

James

 

 

James Pawson

The EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
Consultancy

 

  www.unit3compliance.co.uk  |
 ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

 

 


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[PSES] Risk assessment versus HBSE

[Richard Nute]

 

 

I don’t like the Risk Assessment process because it is highly subjective and 
not very repeatable.

 

When I was with Hewlett Packard, three of us developed “Hazard Based Safety 
Engineering,” HBSE.  The basis for HBSE was James J. Gibson’s (Cornell 
University) research into child injury from auto accidents.  Gibson said:

 

“Injuries to a living organism can be produced only by some energy interchange. 
Consequently, a most effective way of classifying sources of injury is 
according to the forms of physical energy involved. The analysis can thus be 
exhaustive and conceptually clear. Physical energy is either mechanical, 
thermal, radiant, chemical, or electrical.”

 

In a moving automobile, the automobile and its passengers have kinetic 
(mechanical) energy.  In an accident, the kinetic energy of the automobile is 
dissipated in crumpling parts.  The kinetic energy of the passengers is 
dissipated in injuries to the body.  Seat belts transfer the passenger kinetic 
energy to the automobile.  Air bags slow the rate of kinetic energy transfer to 
the automobile.   

 

HBSE identified the magnitudes each kind of physical energy necessary to cause 
injury.  We called this “hazardous” energy.  Then, HBSE went on to specify 
safeguards that would attenuate or prohibit hazardous energy interchange.

 

When I evaluate a product, I look for the physical energy sources, and then 
determine if the energy sources are hazardous or not.  Unlike Risk Assessment, 
this is easy and repeatable and not subjective.  For example, all primary 
circuits are hazardous energy circuits that can cause injury (electric shock, 
thermal, fire, and maybe more) and safeguards must be provided.  

 

Best regards,

Rich

 

 

From: Douglas E Powell  
Sent: Friday, February 11, 2022 11:37 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN 62368-1 : 2020 Ed 3

 

In my view, the Risk Assessment should never be treated as a 'get out of jail' 
card or panacea. Instead, it is only a starting point for a safe design and 
should be done near the beginning of a project, not the end. I agree with what 
Rich says, I've seen a lot of subjective assessments by cross-functional teams, 
with variability based on personal risk tolerance or risk aversion.  There are 
any number of articles pointing to why humans are not very good at assessing 
risk (Google search 
 ). 

 

When using FMEA for risk assessment, I always stress that the RPN factors of 
probability of occurrence, severity, and detection be quantified separately 
without regard to the other factors, not an easy task. There is also the 
problem of RPN vs Criticality (severity x occurrence).  If using the RPN, there 
is the possibility that Detection can dilute the RPN number to a point below 
the threshold for action. So in my view, Criticality alone should be used to 
trigger action. 

 

Kenneth Ross wrote a very good article last month on Navigating the Safety 
Hierarchy; for me, it was an excellent refresher on how I should use risk 
assessment more effectively 
(https://incompliancemag.com/article/navigating-the-safety-hierarchy/).

 

-Doug

 

Douglas E Powell

Laporte, Colorado USA


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Re: [PSES] EN 62368-1 : 2020 Ed 3

[Richard Nute]

 

 

I would say “…risk assessment WILL have variants…”

 

The risk assessment process is subjective.  If you perform a risk assessment on 
an ordinary extension cord, you can find that it is marginally safe.  

 

Rich

 

From: scott...@gmail.com  
Sent: Friday, February 11, 2022 9:14 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN 62368-1 : 2020 Ed 3

 

Hi Charlie,

 

It is pity.  The risk assessment may have variants and inconsistence amongst 
test engineers and make the compliance more difficult.

 

Regards,

 

Scott

 

 


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Re: [PSES] Machinery Leakage Current

[Richard Nute]

 

GFCI = Ground Fault Circuit Interrupter

RCD  = Residual Current Device

 

In North America, GFCI’s typically are included in an outlet that is part of a 
branch circuit.  The GFCI may have a number of outlets downstream.  Under 
normal conditions, the residual leakage current in the downstream outlets and 
equipment connected to them is not zero, and can be a significant portion of 
the 5 mA (nominal) trip current.  So, when a person gets across the 
GFCI-protected branch circuit and causes a trip, the current through the body 
is the difference between the residual leakage current and the 5 ma trip 
current.  So, in such cases, the body current can be much less than the 5 mA 
trip current.

 

The same is the case for the 30 mA RCD in Europe.  However, the RCD is 
installed in the breaker panel for an entire branch circuit, not a portion of 
the branch circuit.  So, the residual leakage current is higher, maybe as much 
as twice that of North America.  And, the voltage, 230, is about twice, so the 
leakage current due to the higher voltage is almost twice that of North 
America.  Using these numbers, the European trip equivalent to the 5 mA trip 
would be about 20 mA or more.   However, the RCD is rated at 30 mA, so when a 
person gets across an RCD-protected circuit, the body current will be much less 
than the 30 mA trip current.

 

Rich

 

 

From: Pete Perkins <0061f3f32d0c-dmarc-requ...@listserv.ieee.org> 
Sent: Thursday, February 3, 2022 1:58 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Machinery Leakage Current

 

Mike, et al, Thanx for mentioning my name; by now you should be able to 
tell the stories as we’ve talked thru these things before.  

 

   From my experience, protection is primarily needed for cord and 
plug connected equipment where the earthing/grounding is not considered 
reliable – which includes North America.  Most such equipment is allowed to 
have higher touch current under fault conditions, where the fault current 
exceeds 5ma the GFCI provides the needed protection

 

   Since GFCIs look for the ‘lost to ground current’, the 
differential current in the power cord, they also work in circumstances where 
the earth/ground doesn’t exist  (a 2-wire installation) or where it should 
exist but doesn’t.  Many are installed in older 2-wire installations because of 
this in the USA. 

 

   RCDs rated to trip at 30mA are working right at the c1 
Ventricular Fibrillation level of IEC 60479-1 so should provide that protection 
for most people.  

 

   Not sure if RCDs are tested or rated for catching performance 
degradation in machines but you apparently have experience with that.  It would 
be nice to see a paper on that performance feature.  

 

   North American GFCIs are rated at 5mA which is the 
letgo-immobilization limit specified in IEC 60479-1.  (Yes, I know the 
allowable range is not trip at 4mA but must trip at 6mA; the rated trip current 
is still 5mA.)  You can still disengage from the current at that level, 
providing that level of protection.  

 

   Both North American GFCIs and Euro RCDs are not rated to deal 
well with high frequency signals generated by Switch Mode Power Supplies and 
Variable Speed Drives for motors.  Lots of ‘nuisance tripping’ results.  There 
is an ongoing UL project to get a handle on this and get it fixed here in NA.  

 

   Yes, EV chargers are being provided with GFCIs at higher levels, 
depending upon the installation/application parameters. 

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 1067

Albany, ORe  97321-0413

 

503/452-1201

 

IEEE Life Fellow

IEEE PSES 2020 Distinguished Lecturer

  www.researchgate.net search my 
name

  p.perk...@ieee.org

 

 

Entropy ain’t what it used to be

 


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Re: [PSES] UL Standards - Old School Spacings

[Richard Nute]

 

 

Hi Doug:

 

I don’t have any history.  But I do have data for how air behaves as an 
insulator and protection methods for creepage distances.

 

The data for air insulation as a function of distance (2000 meters altitude) 
and field shape was given in IEC 664, first edition, 1980.  The data was not 
carried over to later editions.  The upper line is for a homogeneous field, the 
lower line for an inhomogeneous field.  I believe the changes in slope are due 
to anomalies in the measurement method (they should be straight lines).  The 
lines converge at about 327 volts, the Paschen lower limit for air.  (It makes 
no sense to require clearances for voltages below the Paschen limit!)

 



 

Creepage distances were researched by Klaus Stimper, “The physical fundamentals 
of low-voltage insulation co-ordination,” VDE 57, 104 pages.  I have this but 
it is too large a file to send by e-mail.  If you are interested in studying 
this text, I can make this available in Dropbox. 

 

Best regards,

Rich

 

 

 

From: Douglas E Powell  
Sent: Tuesday, January 25, 2022 10:27 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] UL Standards - Old School Spacings

 

All,

 

I'm interested in learning the history behind what I call old school spacings 
found in UL standards. In recent years there has been considerable progress 
toward harmonizing UL spacings to international standards, derived from IEC 
60664-x. However, still today I encounter many UL standards with the old 
spacings table (interpolation is not allowed).

 


Circuit Ratings
V

Minimum Spacings


Through air
Between parts of opposite polarity, 
live and non-current carrying parts 
and live and ground connections
mm (in) 

Over surface
Between parts of opposite polarity, 
live and non-current carrying parts 
and live and ground connections
mm (in) 


30 - 50

1.6 (1/16)

1.6 (1/16)


51 - 150

3.2 (1/8)

6.4 (1/4)


151 - 300

6.4 (1/4)

9.5 (3/8)


301 - 660

9.5 (3/8)

12.7 (1/2)


661 - 1000

19.1 (3/4)

19.1 (3/4)

 

I've had more than a few "discussions" with design engineers about tables like 
this since the numbers seem very arbitrary, and I have to agree. The most 
frequent trouble I have is trying to explain why an increase of just 1 volt 
over 300V results in such a large jump in the over surface requirements. 
Usually I am forced to end with, "it is what it is, and we have to follow the 
rules".

 

Any thoughts? 

 

-Doug

 

Douglas E Powell

Laporte, Colorado USA

  doug...@gmail.com

  LinkedIn

 


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oledata.mso
Description: Binary data


image003.wmz
Description: application/ms-wmz

Re: [PSES] IEEE Xplore access

[Richard Nute]

 

 

I have the same problem.

Rich

Life Fellow

 

 

From: Douglas E Powell  
Sent: Wednesday, December 15, 2021 12:58 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] IEEE Xplore access

 

All,

 

I have been an IEEE member for over 15 years and member of the EMC, PES, and 
PSES societies.  

 

When I visit the IEEE Xplore  I find that many of conference proceedings have 
me locked out.  For example, Symposium on Product Compliance Engineering (PSES) 
 .

 

Being a paid-in-full member, shouldn't I be able to access all those papers?

 

Thanks,  -Doug

 

 

Douglas E Powell

Laporte, Colorado USA

  doug...@gmail.com

  LinkedIn

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Re: [PSES] Will 5G Be Bad for Our Health?

[Richard Nute]

 

 

Hi Manny:

 

Thanks for your comments.  I found that if you replace “non-ionizing radiation” 
with “COVID19” or your favorite issue, the paragraph defines what we all must 
do with various issues.

 

There's a myriad of opinions on the topic of non-ionizing radiation hazards, 
some justified and others not.  When I read an article on this topic the first 
thing I want to try to understand is who wrote it and what is their motivation 
for writing it.  Not saying there's anything nefarious going on, I just want to 
understand some background that will help me interpret what the writer is 
saying and why they're saying it.  And then there's the standards, how they 
were developed, what they are based on, plus their validity.  Every country 
seems to have one, some are identical while others are different.

Stay safe, and best regards,

Rich

 

 

 


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[PSES] Will 5G Be Bad for Our Health?

[Richard Nute]

https://spectrum.ieee.org/will-5g-be-bad-for-our-health





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Re: [PSES] UL 510 Flame retardant tape

[Richard Nute]

 

Hi Charlie:

 

Rather than guess:

 

https://www.kaptontape.com/PDF/Kapton_Films_Datasheet.pdf

https://www.dupont.com/content/dam/dupont/amer/us/en/products/ei-transformat
ion/documents/DEC-Kapton-HN-datasheet.pdf

https://www.dupont.com/content/dam/dupont/amer/us/en/products/ei-transformat
ion/documents/EI-10167-Kapton-General-Specifications.pdf

 

After looking at the above specs, I'm inclined to believe that Kapton tape
will provide an acceptable fire enclosure (as good as any other plastic
material).  It is tough stuff!  And relatively expensive.

 

If you are going to test it (as suggested by Ted), I suggest a side-by-side
test with the alternate fire enclosure plastic material.

 

Note that IEC 62368-1 uses IEC 60695-11-10 for flammability rating rather
than UL 94 and UL 510.  There are no specific requirements for
fire-enclosure tape.  

 

Stay safe, and best regards,

Rich

 

 

 

 

From: Charlie Blackham mailto:char...@sulisconsultants.com> > 
Sent: Friday, October 8, 2021 6:25 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [EXTERNAL] [PSES] UL 510 Flame retardant tape

 

All

 

Various Kapton tapes are sold as Flame Retardant, some seem to reference UL
94 and others UL 510.

 

The scenario is a product falling under EN 62368-1 and the secondary lithium
battery needs a fire enclosure and rather than using the product enclosure,
one could be made for the battery using a suitable plastic or manual
application of retardant tape.

 

Is there any correlation between UL 510 and UL94 when considering creating a
Fire Enclosure for a battery as per Clause M.4.3 ?

 

 

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Mead House

Longwater Road

Eversley

RG27 0NW

UK

Tel: +44 (0)7946 624317

Email:   char...@sulisconsultants.com

Web:
 https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 


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Re: [PSES] Suitable Test equipment for Touch temperature Testing in accordance with EN 62368-1

[Richard Nute]

 

 

Hi Phillip:


As far as I know, 62368-1 does not specify the method for measuring touch
temperatures.  Be aware that certification houses usually measure touch (and
all other) temperatures with a thermocouple.  

 

Stay safe, and best regards,

Rich

 

 

From: Philip Stevenson  
Sent: Wednesday, September 22, 2021 7:42 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Suitable Test equipment for Touch temperature Testing in
accordance with EN 62368-1

 

Dear List Members

 

I am looking for advice of whether the use of an Infra Red (IR) Digital
Thermometer is suitable for performing Touch temperature Testing in
accordance with EN 62368-1. Provided that factors for the different surface
materials are applied to the temperature measurements?

 

If you prefer to reply to me directly instead of vis the listing please do
so at   pw...@hotmail.co.uk. 

 

Thanks in advance for your help.

 

Regards

 

Philip Stevenson

 

 


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Re: [PSES] Creepage and clearance requirements

[Richard Nute]

 

Chances are the isolation between primary and secondary are in place.  But, for 
the purpose of certification, to avoid creepage and clearance requirements 
between primary and secondary, I said to DESIGNATE the secondary as 
non-isolated from the primary.  This does not mean that there is a direct 
connection between primary and secondary.

 

As I understood the unit description, it is a direct-plug-in in a single 
enclosure.  In servicing the unit, one has to recognize the primary circuits 
and the secondary circuits.  Of course, in today’s world, there is very little 
servicing of solid state electronics; replace the whole thing or a board is the 
usual fix.  

 

Rich

 

From: Scott Aldous <0220f70c299a-dmarc-requ...@ieee.org> 
Sent: Tuesday, September 14, 2021 9:19 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Creepage and clearance requirements

 

It's also important to consider servicing operations. If servicing is intended 
on the unit while powered, considering the secondary as not isolated from 
primary (and so not evaluated as a safe circuit) is problematic.

 

On Tue, Sep 14, 2021 at 7:51 AM Pete Perkins 
<0061f3f32d0c-dmarc-requ...@ieee.org 
<mailto:0061f3f32d0c-dmarc-requ...@ieee.org> > wrote:

Amund,I support Rich’s approach.  

 

   It does leave a lingering question, though.  (removing my rose 
colored glasses and putting on my dark, pessimistic glasses)

 

   Imagine a downstream case such as this:  The unit works well and 
is popular.  A customer request comes to the manufacturer something to the 
effect that the unit works well except does not provide the full operational 
reliability in cases where there is significant EMC generated in the use area; 
they ask for an output (USB , PoE, etc) so that they can cable connect the unit 
for these applications.  A (different) company designer believes that this is 
easy to do and starts to work on this project.  If you are lucky, he consults 
the earlier safety lab report to understand the details to properly implement 
this.  

   Where in the report do you clearly state that the requirements, 
including isolation/insulation (creepage and clearance) were not evaluated and 
the ‘secondary’ is considered mains in a clear way?   

   With this understanding the designer will know that the full 
mains isolation/insulation will have to be done for the output circuit since it 
wasn’t done for the mains/secondary interface initially.  (Since, reasonably 
often, the unit won’t meet the mains/secondary requirements in some way and the 
manufacturer will not be willing to change it in this redesign cycle.)

   If this is not clearly taken care of initially then the process 
starts down the slippery slope of believing that everything was completed 
earlier and not fully reviewed at the modification step.  If not caught by the 
designer then the test lab catch will be a major complication in the project 
schedule.  If not caught by the test lab (your associate down the hall) then 
the product is inadequate and does not meet the requirements of the standard; 
hopefully this gets caught in the review but what if it doesn’t?

 

   My point is that simplifications need to be clearly stated in 
the documentation for downstream users.  Don’t leave anything to chance.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 1067

Albany, ORe  97321-0413

 

503/452-1201  

 

IEEE Life Fellow

IEEE PSES 2020 Distinguished Lecturer

 <http://www.researchgate.net/Peter%20Perkins> www.researchgate.net search my 
name

 <mailto:p.perk...@ieee.org> p.perk...@ieee.org

 

 

Entropy ain’t what it used to be

 

From: Richard Nute mailto:ri...@ieee.org> > 
Sent: Sunday, September 12, 2021 3:05 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Creepage and clearance requirements

 

 

 

Hi Amund:

 

If no accessible conductive parts, then you can designate the secondary 
circuits as part of the primary circuits, which means there is no need for 
isolation between primary and secondary circuits.  No creepage or clearance 
requirements!  OVC would not apply primary-to-(a primary) secondary.

 

The plastic enclosure would probably constitute reinforced insulation 
throughout.  For electric shock, you would wrap in foil and measure touch 
current.  Should be comfortably below the limit.  And, you would need to do a 
dielectric test to the same foil at twice the voltage necessary for basic 
insulation.  Should easily pass.

 

I have assumed the antenna is within the enclosure so no accessible conductive 
parts.  If the antenna is an accessible conductive part, then the above 
scenario is not valid.  

 

Stay safe, and best regards,

Rich

 

 

 

 

From: Amund Westin mailto:am...@westin-emission.

Re: [PSES] Creepage and clearance requirements

[Richard Nute]

 

 

Hi Amund:

 

If no accessible conductive parts, then you can designate the secondary 
circuits as part of the primary circuits, which means there is no need for 
isolation between primary and secondary circuits.  No creepage or clearance 
requirements!  OVC would not apply primary-to-(a primary) secondary.

 

The plastic enclosure would probably constitute reinforced insulation 
throughout.  For electric shock, you would wrap in foil and measure touch 
current.  Should be comfortably below the limit.  And, you would need to do a 
dielectric test to the same foil at twice the voltage necessary for basic 
insulation.  Should easily pass.

 

I have assumed the antenna is within the enclosure so no accessible conductive 
parts.  If the antenna is an accessible conductive part, then the above 
scenario is not valid.  

 

Stay safe, and best regards,

Rich

 

 

 

From: Amund Westin  
Sent: Sunday, September 12, 2021 10:16 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Creepage and clearance requirements

 

IEC60950-1:

 

How about the Creepage and clearance requirements for an AC driven radio HUB 
device. 

 

*   One input: 230VAC (direct into wall socket)
*   No physical output ports, just radio communication.
*   Insulated plastic enclosure (UL94 V-0)

 

The Creepage and clearance requirements between primary and secondary circuits, 
does it make any sense as long as the device has no cables and is encapsulated 
by a plastic enclosure

I understand that there should be some Creepage and clearance to withstand OVC 
II (250V transient).

 

Best regards Amund

 

 


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Re: [PSES] Over Reliance on Automated Safety Controls (Friday question)

[Richard Nute]

 

Hi Doug:

 

For safety, the issue seems to be reliance on the correct functioning of 
devices.  

 

As equipment becomes more and more complex, we are more reliant on the correct 
functioning of devices.  An example is the modern day airplane.  One specific 
example is the Air France flight from Buenos Aires to Paris.  A pitot tube 
stopped working, so the airspeed indicator stopped working.  The plane crashed 
into the Atlantic Ocean.  

 

However, the cause of the crash was pilot error in dealing with the loss of the 
airspeed indicator.  

 

The problem seems to me to be that we don’t understand the consequences and 
necessary action when we incur a functional safety failure.  We are lulled into 
believing that functional safety cannot fail, and so we do not have an action 
plan in case of the failure.

 

Rich

 

 

From: Douglas E Powell  
Sent: Friday, September 3, 2021 7:00 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Over Reliance on Automated Safety Controls (Friday question)

 

All,

 

My question is probably philosophical.

 

With the advent of Safety rated PLCs, Safety Relays, and other solid state and 
programmable safety devices in certified and listed products, are we at risk of 
becoming over reliant on automated safety systems. I'm thinking in terms of IEC 
61508, ISO 12100, UL 1998, UL 991, and many others. While I agree that use of 
programmable devices for safety control is in our future, it seems we, as a 
society, are putting a lot of reliance in this. It is well known that zero risk 
is impossible, but it also seems that "people these days" routinely ignore the 
risks, and it is my view that humans have a very bad history of correctly 
estimating risk out in the wild. It's not my intention to pick on autonomous 
vehicles only, since I've seen this sort of care-less behavior played out in 
other places as well. 

 

Some keywords I have in mind:

*   Automation Dependency
*   Automation Bias
*   Automation Induced Complacency

In general, do you feel we are becoming a society that relies too much on 
technology and automation to keep us safe from harm? I'm looking for an open 
discussion on this and what do you feel will be in store for us in the future.

 

-Doug

 

 

Douglas E Powell

Laporte, Colorado USA

  doug...@gmail.com

  http://www.linkedin.com/in/dougp01


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Re: [PSES] Touch temperature limits for accessible parts

[Richard Nute]

 

Hi Scott:

 

A 1st degree skin burn occurs when skin temperature is 44 C.  Plastic material 
has relatively high thermal resistance.  80 C plastic is unlikely to cause a 
burn regardless of contact time.  In a separate message, I will send separately 
my paper on thermal injury from the 2014 ISPCE.  From this you can calculate 
whether or not a burn will occur.  

 

Stay safe, and best regards,

Rich

 

Ps:  A charger running at more than 80 C is poorly designed.   

 

 

From: Scott Xe  
Sent: Thursday, September 2, 2021 6:02 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Touch temperature limits for accessible parts

 

I am looking for advice on temp measurements and the requirements. I have an 
in-car charger with a temp of 80 degC on external plastic enclosure at max 
load.  Referring to EN 62368-1, the max temp is from 48 - 94 degC depending on 
the time to be touched to operate the equipment.  During operation, it is 
unnecessary to touch the external enclosure except plugging in and taking out 
from cigarette socket.  Is it deemed to apply 94 degC?

 

Should the max temp be measured at room temp of 25 degC or the maximum 
operating temp?  If at max operating temp, how to derive the max temp limits in 
such conditions?

 

Thanks and regards,

 

Scott


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Re: [PSES] Multiple Power cord-sets bundled with product Redux UK Plugs BS 1363 as the standard plug

[Richard Nute]

 

Hi Chuck:

 

https://spectrum.ieee.org/why-does-the-world-harbor-so-many-different-voltag
es-plugs-and-sockets

 

https://www.iec.ch/world-plugs

 

Stay safe and best regards,

Rich

 

 

 

 

From: Chuck August-McDowell  
Sent: Wednesday, August 4, 2021 7:50 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Multiple Power cord-sets bundled with product Redux UK
Plugs BS 1363 as the standard plug

 

Dear List members,

 

I found the information in this thread very useful especially the "mutually
exclusive" designations.

 

I am writing today seeking comments on UK Plugs BS 1363 as the standard plug
and cordage to ask if any are also known "mutually exclusive" issues.

For example between United Kingdom, Saudi Arabia, Singapore?

 

Thank you in advance,

 

Chuck August-McDowell

 


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Re: [PSES] Friday question

[Richard Nute]

 

 

Hi Doug:

 

My employer had a course entitled “Zero Defects.”  We were encouraged to apply 
it to our function.  Mine, of course, was safety certification and all that it 
entailed.  Good course as it wanted a scorecard for each activity.  

 

Using the scorecard, all my submittals went without action items.  Okay, a few 
action items that I successfully showed them where they were wrong.  I took to 
arguing with the cert engineer.  In one case, he wouldn’t accept my argument, 
so I took the product to another cert house and was successful.

 

I applied the same process to follow-up inspections.  After a year or so of no 
defects, the certification house was upset.  So, they sent a bigwig to 
accompany the inspector (probably to check whether I was intimidating the 
inspector).  No defects!  

 

Rich

 

 

From: Douglas E Powell  
Sent: Friday, June 25, 2021 10:55 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Friday question

 

Out of curiosity, 

 

I would like to know (especially from those who have been in the business for a 
while) what is your "first pass success rate" for safety certifications on new 
product introductions? That is, to achieve a product safety certification from 
an accredited laboratory with no action items required coming out of the 
preliminary design review.  It's helpful if you can indicate how complex the 
projects are.

 

In my 26 years as a compliance engineer, I've observed possibly three in total 
for products with a reasonably high complexity.

 

Thanks! Doug

--

 

Douglas E Powell
doug...@gmail.com  
http://www.linkedin.com/in/dougp01

 

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Re: [PSES] What percentage of products pass first time?

[Richard Nute]

 

 

Hi John:

 

“Therefore safety, standards compliance and EMC standards compliance REALLY 
MUST be an integral component of engineering education – and ALSO for company 
management…”

 

While I agree, in practice the only time company management addresses safety 
and other compliance matters is when an incident becomes public.  The usual 
public response from management is that “safety is foremost at our company.”  
BS!  The foremost items are: profits and growth.  A safety incident takes 
management time (reluctantly) away from profits and growth.

 

Compliance is an engineering and manufacturing process just as and equal to any 
other engineering and manufacturing process.  If done competently, it has no 
special effect on the schedule.  So, management has no need for special 
interest in compliance.  What is important is that management hires competent 
compliance employees.  

 

Stay safe, and best regards,

Rich

 

 


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Re: [PSES] What percentage of products pass first time?

[Richard Nute]

 

Hi Charles:

 

Not what you asked for, but a set of principles for success with third-party 
testing, from a product safety point of view:

 

1.  The design engineer and the product safety engineer should be able to 
predict the outcome of any test.
2.  Testing simply confirms (or not) the prediction.
3.  Failure of a test or other requirement at the third-party delays the 
third-party investigation which can imperil the product schedule.  To maintain 
schedule, the product must comply with all tests before it is submitted to the 
third-party.
4.  If the product that you successfully tested fails a third-party test, 
then your or the third-party test was in error.  This can open a dialogue 
between you and the third-party as to test process.
5.  Tests to standards requirements are either pass or fail; always record 
the measurement.  If the test requires a stimulation, then adjust the 
stimulation to the point of failure and record the measurement.  Both tell you 
the margin between pass and failure.  
6.  Provide your measurement data to the third-party when you submit the 
product.  If the third-party measurement data differs from your data, some 
third-parties will do their own investigation as to why.  

 

In my opinion, EMC is not a black art and can follow these same principles.

 

Stay safe, and best regards,

Rich

 

 

 

 

From: Grasso, Charles [Outlook]  
Sent: Monday, May 24, 2021 7:47 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] What percentage of products pass first time?

 

Hello EMC gurus!

 

Calling all labs - In your experience how many products pass the Unintentional 
Emissions
test first time? ​

 

 

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Re: [PSES] Ganged Conductors in Machinery

[Richard Nute]

 

 

Hi Mark:

 

Here’s a start:

 

https://www.ecmag.com/section/codes-standards/conductors-connected-parallel-
each-set-must-have-same-electrical

 

https://www.electricallicenserenewal.com/Electrical-Continuing-Education-Cou
rses/NEC-Content.php?sectionID=297.0

 

https://www.ecmag.com/section/codes-standards/derating-parallel-conductors

 

https://iaeimagazine.org/features/parallel-conductors-revisited/

 

Stay safe, and best regards,

Rich

 

 

 

 

 

 

From: Stultz, Mark <0f79f2e10e47-dmarc-requ...@listserv.ieee.org> 
Sent: Wednesday, May 19, 2021 9:05 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Ganged Conductors in Machinery

 

Hello all,

 

Is it permissible to combined separate conductors to carry a load in
parallel within machinery?  If it is allowable, what derating would be
required?  I can’t find reference to this in IEC 60204-1 or NFPA 79.

 

Many thanks,

 


 

 


Mark Stultz

10175 Philipp Parkway


Senior Mechanical Development Engineer

Streetsboro, OH 44241


CMSE® – Certified Machinery Safety Expert (TÜV NORD)

330-342-2402


Automated Packaging Systems

 


 

 




 

 


  autobag.com

  SealedAir.com

 

 

 


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Re: [PSES] South African SABS EMC Testing

[Richard Nute]

 

Hi Carl:

 

I cannot confirm that the SABS accreditation requires re-testing.

 

However, this not unusual.  I have experienced this same situation in safety 
testing.  If a failure, the complete complement of tests is repeated on the 
“fixed” unit or another unit.  The test house doesn’t know whether the fix 
affected the other test results.  

 

Sometimes, only the fix is tested again – if the test house makes a 
determination that the fix is unlikely to affect the other test results.  They 
will consider your rationale that the fix does not affect the other test 
results, but not necessarily accept your rationale.

 

Stay safe, and best regards,

Rich



 

From: Carl Newton  
Sent: Monday, May 17, 2021 11:52 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] South African SABS EMC Testing

 

Group,

I'm writing to ask if anyone in the group is familiar enough with South African 
SABS EMC testing through accredited labs to answer my question regarding 
sequence of testing.  I'm trying to get an ITE setup through a major USA NRTL 
EMC lab in order to get the SABS EMC Certificate of Compliance.  We had a 
radiated emissions issue after the conducted emissions testing was completed 
upon AC mains and Ethernet port.  The hardware setup was returned to the 
manufacturer and subsequently returned to the EMC lab without change.  Now the 
EMC lab is telling me that their SABS accreditation demands that all conducted 
emissions be repeated because the hardware setup left the lab's possession (and 
adjusted their quote accordingly). 

Can anyone on the list here confirm that SABS lab accreditation mandates this 
type of action?

Thanks,

Carl


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Re: [PSES] EU DoC on Thumb Drive?

[Richard Nute]

 

 

The symbol ISO 7000-3500  "Electronic instructions for use" is for medical 
equipment.  The related EU regulation is:

 

https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:072:0028:0031:EN:PDF

 

This regulation specifies, among other requirements, “exclusive use by 
professional users” and requires a risk assessment.   

 

If your equipment is not medical equipment, you cannot (or should not) use the 
symbol.  

 

I know of no regulation that prohibits electronic instructions, but standards 
and regulations specify statements which are traditionally printed on paper and 
which must accompany the equipment.

 

Stay safe, and best regards,

Rich

 

 

From: Chuck August-McDowell  
Sent: Friday, May 14, 2021 11:42 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EU DoC on Thumb Drive?

 

Seconding Brian’s motion to allow the QR Code as an approved method to provide 
DoC information.

 

We recently Include Symbol ISO 7000-3500  "Electronic instructions for use" and 
the QR Code in the Symbol table in the basic safety information provided on 
paper with each product.

Currently provide paper DoC also.

 

Symbol ISO 7000-3500 Function/description : 

To indicate on product or product packaging that relevant information for use 
of the product is available in electronic form rather than, or in addition to, 
printed paper form. 

 

Link   
https://www.iso.org/obp/ui#iso:grs:7000:3500

 

 

Respectfully,

 

Chuck August-McDowell

 

 

From: Pete Perkins <  
0061f3f32d0c-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, May 14, 2021 10:51 AM
To:   EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EU DoC on Thumb Drive?

 

[EXTERNAL EMAIL]

Brian,This is another method that needs to be on the list of accepted paths 
to show compliance, in my opinion.  

 

   Of course, the acceptance for any such methods need to come from 
the Euro Commission, meeting Euro legal requirements and having the buy-in of 
all the interested parties – such as the Customs Officers who are charged with 
either clearing or refusing entry to CE marked items and are looking for 
further justification (MDoC in particular).  

   I see this as a long slog to get anywhere unless some very 
influential group that the EU folks admire takes it on with a passion.  Do you 
know anyone at the WTO?  

 

   I guess, if your company is gutsy enough you can try it and see 
how it goes; sometimes changes are made in fact and later the paperwork catches 
up.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 1067

Albany, ORe  97321-0413

 

503/452-1201

 

IEEE Life Fellow

IEEE PSES 2020 Distinguished Lecturer

  www.researchgate.net search my 
name

  p.perk...@ieee.org

 

 

Entropy ain’t what it used to be

 

From: Brian Ceresney <  bceres...@delta-q.com> 
Sent: Friday, May 14, 2021 10:40 AM
To: Pete Perkins <  peperkin...@cs.com>;  
 EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] EU DoC on Thumb Drive?

 

Hello All, 

Apologies for “hijacking the thread”, but we’ve been considering the 
now-ubiquitous(post pandemic) QR Code as a method of delivering information 
about the product – user manual, declarations for the EU, MC documentation, 
etc. A small accessible code label could really help make information 
accessible to the customer, using the cell phone. 

Does this also still fall under the “not-yet” category?

 

Best Regards, 

Brian C.

From: Pete Perkins <  
0061f3f32d0c-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, May 14, 2021 10:34 AM
To:   EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EU DoC on Thumb Drive?

 

CAUTION: This email originated from outside of the organization. Do not click 
links or open attachments unless you recognize the sender and know the content 
is safe.

 

Carl et al,

 

   This question has been asked before and the official answer 
seems to still be ‘not yet’.  

 

   Some folks in the IEEE PSES TAC/ITE interest group have been 
working to put together a draft proposal that would allow digital documentation 
(thumb drive or even website) to meet the requirements.  As noted, there are 
many interests in this way outside our usual working circle.  Nothing has 
developed from this yet; maybe sometime in the future.  

 

   Keep your hopes up though; pie in the sky is what keeps us going 
some time.   

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 1067

Albany, ORe  

Re: [PSES] Ground Bond Tests

[Richard Nute]

 

Hi Steve:

 

First, one of my clients has been told by their 3rd party NRTL that a ground 
bond test is required as part of factory/production routine tests, even though 
it is not required by 61010-1.  I have never run into this requirement in my 
work history and I would be interested in hearing if any of you have. 

 

In my experience, which dates back to UL1244 and UL478, no standard specified 
routine production tests.  Nevertheless, our contract with UL and CSA required 
hi-pot and grounding continuity tests.  These production tests have been 
implemented ever since then.  Regardless of the standard, the NRTL can demand, 
through its contract with the manufacturer, production-line tests.  

 

Second, just to be sure my interpretation is correct, 61010-1, section 6.5.2.4, 
Impedance of protective bonding of plug-connected equipment, in the fist 
sentence, it has a limit of 100 mOhms impedance and my read is that this is for 
equipment with a power cord that has a plug on one end and a receptacle on the 
other. 

 

In my experience, the protective bonding impedance measured from any grounded 
part (whether accessible or not) to the main protective bonding terminal (where 
the power cord terminates on the equipment end) is 0.1 ohm maximum.  The power 
cord protective conductor resistance is not included in the equipment bonding 
impedance measurement.   (8 feet of #18 stranded copper wire is 0.051 ohms, 
half of the 0.1 ohm requirement.)  

 

(Back in the “old days” for me, the bonding impedance, including the power 
cord, was 0.5 ohm.)  

 

In the May, 2014, Symposium, I presented “Equipotentiality and Grounding, 
Derivation of grounding resistance for equipment.”  If you don’t have a copy, I 
will be happy to forward a copy of either the presentation or the paper or 
both.  

 

(As an aside, only the fault current path need meet the impedance criterion.   
Those grounded parts that are not in the fault-current path need not be tested. 
 And, those grounded parts that are separated from mains by double or 
reinforced insulation are not required to have 0.1-ohm impedance to the PE 
terminal or subject to the routine test.  However, such testing may be 
expedient for a production-line test.)  

 

(I had a ground impedance failure on a PCB by a NRTL.  The test was not the 
current path.  We pointed this out; the test was repeated on the actual current 
path and passed.)

 

Then, in the same section, still under the title of plug-connected equipment, 
it says for equipment that has a non-detachable power cord  the limit is 200 
mOhms.  My interpretation is that plug-connected equipment with a 
non-detachable power cord is when the power cord is hard wired to the unit 
under test, but still has a plug for mains connection. 

 

The 0.2 ohm limit accounts for both the resistance of the power cord and the 
impedance of the equipment.  I agree with you that a non-detachable power cord 
is hard-wired the equipment.  

 

Stay safe, and best regards,

Rich

 

 

 

 


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Re: [PSES] UL Standards Effectivity Dates

[Richard Nute]

 

 

Hi Doug:

 

In my opinion:

 

1.  UL certifications for a particular equipment are good for the lifetime 
of the equipment, and don’t need to be updated… unless...  
2.  If the equipment is refurbished or updated, UL has a program to update 
the certification to the latest version of the original standard.

 

Stay safe, and best regards,

Rich

 

 

From: Douglas E Powell  
Sent: Thursday, May 6, 2021 12:16 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] UL Standards Effectivity Dates

 

Hello all,

 

I would like to understand the use of effectivity dates, specifically for UL 
standards, when dealing with rather large leased equipment used in association 
with an energy production facility. The plan is that an original manufacturer 
will build, install, monitor, and maintain the equipment as a lease and not for 
sale. The idea is that the equipment is put into service with the required 
certifications of the day.  

 

If at some later time, possibly a few years later, the equipment is taken out 
of service, moved to a new location to be put into service once again (the 
ownership has not changed) and if in that interim period the applicable product 
standards have been revised, effectivity dates established, and the new edition 
of the standard is mandatory for new products, is it necessary to re-certify 
that equipment?  

 

In my scenario that equipment may or may not involve refurbishing or updating 
when it is relocated. 

 

Thanks, Doug

 

-- 

 

Douglas E Powell
doug...@gmail.com  
http://www.linkedin.com/in/dougp01


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Re: [PSES] Schuko CEE 7/7 Plugs for Appliances Sold in Italy?

[Richard Nute]

 

See:

 

https://www.worldstandards.eu/electricity/plug-voltage-by-country/

 

https://www.iec.ch/world-plugs

 

The US Dept of Commerce used to annually publish a book with all the world 
plugs, but I can’t find it.  

 

Stay safe, and best regards,

Rich

 

From: MIKE SHERMAN  
Sent: Thursday, April 29, 2021 3:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Schuko CEE 7/7 Plugs for Appliances Sold in Italy?

 

Is it legal to appliances in Italy that have Schuko CEE 7/7 plugs? 

All my Wikipedia research says that this is common. 

Is there a government regulatory body that can answer this? I could not find an 
answer on the mise.gov.it website, or a contact to ask. 

  

Thanks!
Mike Sherman 

Graco Inc. 


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Re: [PSES] Determination of Maximum transient voltage on naval ships

[Richard Nute]

 

 

Hi Charlie:

 

If the ship can be connected to shore power, then the ship may be subject to
"normal" (shore-based) transient voltages, in which case your equipment must
meet the clearances for 2,000 volts peak.  However, the specified at-sea
ship-board 1,000 volts peak is reasonable since lightning strikes on
overhead wires is unlikely.

 

According to Table 10, the clearance dimension for 1,000 volts peak is 0.26
mm (0.8 mm for pollution degree 3), and for 2,000 volts peak is 1.2 mm.
These are very small distances.  Chances are the equipment has clearances
greater than 1.2 mm, so it meets both 1,000 and 2,000 volts peak criteria.
(Dimensions of a fraction of a millimeter require special control.)  

 

If you are planning on third-party certification to 62368-1, I would expect
that the certification house would insist on 2,000 volts peak and the 1.2 mm
clearance despite ship-board 1,000-volt transient voltage. 

 

Stay safe, and best regards,

Rich

 

 

 

 

From: Charlie Blackham  
Sent: Wednesday, March 3, 2021 8:23 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Determination of Maximum transient voltage on naval ships

 

All

 

I'm currently doing a LVD safety assessment for a rack of Radio
Communication equipment going onto naval ships and using EN 62368-1

 

The equipment is powered at 115 60 Hz

 

Clearance distances are based on maximum transient voltages which for normal
(shore based) installations is given as 2000 V for 115 V installations per
EN 62368-1 clause 5.4.2.2 referencing 5.3.3.2.3 of IEC 60664-1:2007

 

The 115V AC system on a ship is not subject to the same over voltage
transients as land based equipment

 

Google has found US publication  S9086-KY-STM-010/CH-320R2
 , Naval Ships'
Technical Manual Chapter 320 Electric Power Distribution Systems

Maximum voltage transient of 1000 V on 115 V systems - this is also in
MIL-STD-1399-300-1
  TABLE II. Characteristics of shipboard electric power systems

 

I'm basically trying to determine the minimum Clearance requirements to be
applied so that the client can CE mark the system - is it reasonable to use
this 1000V for determining required clearance in Table 11?

 

Or, any reason why it's not reasonable ? 

 

Thank you in advance for your thoughts

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Mead House

Longwater Road

Eversley

RG27 0NW

UK

Tel: +44 (0)7946 624317

Email:   char...@sulisconsultants.com

Web:   https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 


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Re: [PSES] Electrical safety certification for US / Canada

[Richard Nute]

 

USA:

https://www.osha.gov/nationally-recognized-testing-laboratory-program/current-list-of-nrtls

 

Canada:

https://www.scc.ca/en/accreditation/programs/product-process-and-service-certification/directory

 

For both countries, check the standards or products for which a certification 
house is qualified.

 

 

From: Amund Westin  
Sent: Tuesday, February 16, 2021 1:55 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Electrical safety certification for US / Canada

 

The following can issue Electrical safety certifications:
CSA
UL
FM

Any others?

It's IT-products.

BR
Amund


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[PSES] FW: Help with petition to be an IEEE President Elect candidate in 2021

[Richard Nute]

See following message.  You must be an IEEE member to sign the petition.  

After you log in to your IEEE account, you will get the petition page.  Click 
on the "Annual Election Petition," and you will get the petition page.  

Best regards, and stay safe!
Rich


-Original Message-
From: Tom Coughlin  
Sent: Friday, January 22, 2021 9:54 AM
To: ri...@ieee.org
Subject: Help with petition to be an IEEE President Elect candidate in 2021

Hello folks and best wishes for 2021!  

I am an active and long-time IEEE volunteer, involved and very productive in 
MGA, TA, SA and IEEE-USA activities.  I am seeking to get on the ballot to run 
for IEEE President Elect in 2021.  You can find the petition here:  
www.ieee.org/petition.  IEEE graduate students and higher grade members can 
sign the petition.

If you do sign my petition it would be a great help if you could post a note 
like this to your social media or pass on this email to others:  “I’m 
supporting the petition to include Tom Coughlin on the IEEE President-elect 
slate of candidates.  Please add your signature to his petition 
(www.ieee.org/petition).  This is not an election vote.  It adds Tom to the 
ballot.”

You can find out more about me at https://tomcoughlin.com/ieee  This page gives 
information about my IEEE activities, a link to the petition and information on 
why I want to run.

Thanks for your attention and best wishes!

Coughlin Associates
www.tomcoughlin.com
1665 Willowmont Ave
San Jose, CA 95124
USA

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Re: [PSES] UL = IEC ??

[Richard Nute]

 

Hi Amund:

 

First and foremost, both the IEC and UL make money selling standards.

 

Second, UL does not adopt any IEC standard, or most other non-UL standards.

 

UL will test to an IEC standard, and may issue a CB test report, but not the
right to use their certification mark.  UL will only issue the right to use
their certification mark if the product meets the UL standard.  

 

UL writes their own standards.  If industry insists, UL will start with an
IEC standard and re-write it to meet their requirements (often justified as
meeting USA National Electrical Code requirements).  To be fair, Americans
often add more requirements, too (which are gladly accepted by UL as such
additional requirements mean additional testing and additional income).  

 

UL is an ANSI-approved standards-writing organization.  As such, virtually
all UL standards are also ANSI standards.  All other certification houses
must use UL/ANSI standards for their certification. 

 

Best regards, and stay safe!

Rich

 

From: Amund Westin  
Sent: Thursday, January 21, 2021 2:40 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] UL = IEC ??

 

When IEC publish a standard, do UL adopt it as is, or do they modify it? I
guess this will vary form case to case. Right?

 

Best regards Amund


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Re: [PSES] NFPA Codes, law or not?

[Richard Nute]

 

 

Hi Doug:

 

If I remember correctly, the intro to the NEC says that it is a model for 
adoption by various AHJs.

 

In Oregon, each edition of NFPA 70 is formally adopted with exceptions and 
additions.  So, most of NFPA 70 is law.  The amendments are freely available.  
Many other jurisdictions do the same.  

 

 

 2017 Oregon Electrical Specialty Code (OESC)
Effective Oct. 1, 2017
Based on the 2017 NFPA 70, National Electrical Code
  
Oregon amendments to the 2017 NEC Updated Oct. 2020

 

Stay safe!

Rich

 

 

 

From: Douglas Powell  
Sent: Friday, October 30, 2020 7:00 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] NFPA Codes, law or not?

 

My Friday Question,

 

NFPA Codes, law or not? Officially the answer is, "No, these are not laws." 

 

I recently saw a clarification stating:

"As a national consensus safety standard, NFPA 70 is not a law and it has not 
been incorporated into the Code of Federal Regulations. Therefore, compliance 
is not deemed mandatory. Even so, OSHA has cited NFPA 70 in cases where lack of 
compliance has resulted in a workplace accident." 

 

The National Fire Protection Association (NFPA) is a nonprofit organization and 
not a government entity. In the USA, possibly the best known published document 
is the NFPA 70 which is the National Electric Code or NEC ®. And indeed, this 
code has been translated and adopted in other countries in places like Latin 
America 

 . Nevertheless, in my view, the whole system is bordering on becoming a legal 
requirement, especially at the local level where Authorities Having 
Jurisdiction (AHJs) adopt these into their local city and county codes.  

 

Occasionally a discussion is raised on electrical forums where someone wants to 
point out that in this country any code which is officially mandated law must 
be freely available for public use. NFPA does indeed offer a "free view" but 
these are very deficient with regard to usability. 

 

The question then becomes, "Should these codes be law?

 

Food for thought...

 

Doug

 

-- 

 

Douglas E Powell

doug...@gmail.com  
http://www.linkedin.com/in/dougp01


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[PSES] electric shock from capacitor discharge -- late adds

[Richard Nute]

 

Here is a summary of capacitor discharge situations with late adds:

 

Operator conditions:  Vacuum tube radio/tv with isolated metal trim.  (John 
Woodgate)

Service conditions:  Vacuum tube radar servo controller.  (Doug Powell)

Service conditions:  UPS capacitor discharge (automatic or time delay) before 
servicing.  (Bansi Patel)

Operator conditions:  Defibrillator automatic discharge. (Dave Osborn)

Operator conditions:  CRT capacitance.  (Mike Sherman) (Dan Roman)

Service conditions:  Power factor correction capacitor for motor drives  (Ted 
Eckert) (Julia Curson) (Mike Sherman)

Service conditions:  Small ion implanters.  (Lauren Crane)

Service conditions:  Microwave oven capacitors with integrated bleeders.  (Adam 
Dixon)

Service conditions:  Electrostatic speaker amplifiers.  (Adam Dixon)

Service conditions:  Electric welding systems.  (Adam Dixon)

Service conditions:  Industrial laser systems.  (Inadvertently omitted from 
first list).)  (Pete Perkins)

 

Adam (in Atlanta) Dixon sent a URL of a capacitor discharge event that is 
worthwhile reading.  Note the picture of the capacitor!

 

https://ehs.berkeley.edu/lessons-learned/lesson-learned-injury-caused-high-voltage-capacitor-discharge

 

 

We still need to identify in our safety standards when a charged capacitance 
requires a safeguard.  For operator conditions, we need automatic discharge as 
is done for defibrillators.  For service conditions, we need either an 
automatic discharge safeguard or an instructional safeguard.  (We can ignore 
vacuum tube devices and crt devices as it is doubtful any new products will use 
such devices!)

 

Thanks for your responses.

 

Stay safe!

Rich

 

 

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Re: [PSES] electric shock from capacitor discharge

[Richard Nute]

 

 

Here is a summary of capacitor discharge situations:

 

Operator conditions:  Vacuum tube radio/tv with isolated metal trim.  (John 
Woodgate)

Service conditions:  Vacuum tube radar servo controller.  (Doug Powell)

Service conditions:  UPS capacitor discharge before servicing.  (Bansi Patel)

Operator conditions:  Defibrillator automatic discharge. (Dave Osborn)

Operator conditions:  CRT capacitance.  (Mike Sherman) (Dan Roman)

Service conditions:  Power factor correction for motor drives  (Ted Eckert) 
(Julia Curson) (Mike Sherman)

Service conditions:  Small ion implanters.  (Lauren Crane)

 

We still need to identify in our safety standards when a charged capacitance 
requires a safeguard.

 

Thanks for your responses.

 

Stay safe!

Rich

 

 


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Re: [PSES] EMF harmonised standards

[Richard Nute]

 

 

Hi Brian:

 

Be careful that the customers’ requests are not just asking by rote.

 

Way back when, we had customers asking about UV emissions from a crt.  Most 
glass is a good attenuator of UV, but the asking (non-technical) customers were 
asking because someone in their company asked them to ask.  These customers 
were satisfied with a non-technical answer that said that no UV came through 
the glass rather than a measure of the UV.  

 

Perhaps your customers are of this sort?  Perhaps a simple answer as you said 
in your message will satisfy your customers.  If not, they will come back to 
you with a request for data.  

 

Good luck, and stay safe!

Rich

 

 

From: Brian Kunde  
Sent: Thursday, October 1, 2020 8:30 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EMF harmonised standards

 

When do you know if a product needs to be tested to these standards or not?  
What requires this testing?  Is there a criteria that can be used?  Does the 
SCOPE of these standards make it clear if and when the standards need to be 
applied to a product?   We have had customers request it but most electronic 
equipment doesn't put out enough magnetic or electromagnetic fields to even 
make it onto the graph?  Seems like a waste of time for most electronics unless 
they incorporate high current or high power RF transmitters.  

 

Brian

 


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Re: [PSES] electric shock from capacitor discharge

[Richard Nute]

 

 

Hi Lauren:

 

Thanks, but I recognize that many standards include such requirements.  I am 
looking for instances (other than the pins of a power plug) where such 
requirements must be invoked. 

 

Stay safe!

Rich

 

From: lauren.cr...@us.tel.com  
Sent: Tuesday, September 29, 2020 2:52 PM
To: ri...@ieee.org
Cc: EMC-PSTC@listserv.ieee.org
Subject: Re: [PSES] electric shock from capacitor discharge

 

Hi Rich, 

 

Discharge requirements are already in some electrical safety standards. Not at 
my desk so recall is poor, but likely 61010 or even NFPA 79 have something 
about caps with stored energy above x joules have to discharge within N seconds 
of power off...

 

Cheers,

-Lauren

Sent from my mobile phone - please excuse typos, brevity, etc.





On Sep 29, 2020, at 4:27 PM, Richard Nute mailto:ri...@ieee.org> > wrote:

 

I am interested in knowing what constructions, situations, and products where a 
capacitive discharge into a body could take place.

I am aware of the X and Y capacitors discharge at the prongs of a power plug.  
I don’t immediately know of other situations or products that might discharge a 
capacitor into a body.  

I would appreciate descriptions of such discharges into a body, not conjecture. 
 Preferably, normal conditions and some single-fault conditions.  

Do we need to include capacitive discharge requirements in the safety standards?

Stay safe!

Rich






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Re: [PSES] Low Voltage Products and EN 62368-1 and -3

[Richard Nute]

 

 

Hi Scott:

 

Certification is not a function of the safety standard; it is a function of the 
certification house.  Most certification houses would be happy to certify a 
low-voltage product.  

 

Keep in mind that the various safety standards also address matters other than 
electric shock.  62368-1 has separate clauses that address heat, fire, 
stability, etc., so these other matters are clearly visible.  If your EPS is 
rated for 4 amps at 12 volts, you have 48 watts available under normal 
conditions and probably 100 watts under fault conditions.  Under 62368-1, the 
ITE would (should!) be evaluated for both fire and hot accessible parts.  

 

Required by 62368-1?  No.  But, a good idea; it’s easy, relatively fast, 
relatively cheap, and keeps the questions from being asked.

 

Stay safe!

Rich

 

 

From: Scott Douglas  
Sent: Tuesday, September 29, 2020 1:52 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Low Voltage Products and EN 62368-1 and -3

 

Esteemed colleagues,

 

Question on EN 62368-1 and -3 related to low voltage products.

 

Products are ITE equipment with power requirement of 5v or 12v DC and less than 
4 amps, sometimes they are powered by PoE. We ship some of these products with 
an external power supply 120/230 V~ input and 5 or 12 VDC output. The EPS 
always have full certifications to normal safety standards including 62368-1. 
Other times we do not include an EPS with the product.

 

One of our factories is trying to tell us that under IEC/EN 62368-1 or -3, our 
products are required to have safety certifications, that having just the EPS 
certified to 62368-1 is not enough.

 

We have always said that since these are low voltage products (even the PoE 
ones) that safety certifications are not required for the products themselves.

 

Has something changed where these type products are now required to have safety 
approvals for the EU or US/Canada markets? Or since they are not directly 
connected to the AC Mains, they do not need safety approvals?

 

Looking for someone to either confirm my sanity or teach me a new lesson. All 
comments welcome.

 

Scott

 


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[PSES] electric shock from capacitor discharge

[Richard Nute]

I am interested in knowing what constructions, situations, and products
where a capacitive discharge into a body could take place.

I am aware of the X and Y capacitors discharge at the prongs of a power
plug.  I don't immediately know of other situations or products that might
discharge a capacitor into a body.  

I would appreciate descriptions of such discharges into a body, not
conjecture.  Preferably, normal conditions and some single-fault conditions.


Do we need to include capacitive discharge requirements in the safety
standards?

Stay safe!
Rich



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Re: [PSES] IEEE 291

[Richard Nute]

 

 

Hi John:

 

Two questions:

1. Can an IEEE member get to see IEEE 291, even if it's only 'read only',
free of charge?

No.  I am an IEEE member and I cannot get any free copy of IEEE 291.  By the
way, it was withdrawn on January 16, 2004.  

2. Is its contents superseded by part of IEEE C63.4-2014?

The web does not mention whether 291 is superseded by C63.4 at any of the
respective web sites that I reviewed.   

You might be able to get a committee draft from the C63.4 working chair Don
Heirman.  I'm sure that he can answer your second question.

http://www.c63.org/documents/misc/matrix/c63_standards.htm

Stay safe, and best regards,

Rich

 


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Re: [PSES] EN/IEC 62368-1 Instructional Safeguards

[Richard Nute]

 

 

Hi Jim:

 

IEC 62368-1 contradicts itself.

 

In 8.5.2, the standard specifies two symbols (for moving pats).

 

In F.5.2, the standard references graphical symbol standards, and gives the
option of designing a specific symbol.

 

So, the question is: Which sub-clause takes precedence?  

 

Clause 8 was written by an ad hoc group.  Annex F was written by another ad
hoc group.  The two groups did not review each other's work, and the editing
committee did not thoroughly review the two clauses.  If all had done a
thorough job, we would not have this contradiction.  (Such contradiction is
not unique to 62368 but can be found in other IEC safety standards.)

 

Regardless of the contradiction, keep your customer in mind, and choose a
symbol that will clearly warn your customer.  

 

Good luck.  Stay safe.  Best regards,

Rich

 

 

From: Jim Hulbert  
Sent: Thursday, June 25, 2020 12:31 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] EN/IEC 62368-1 Instructional Safeguards

 

EMC-PSTC group, 

 

This  question is in regard to EN/IEC 62368-1 instructional safeguards.  In
section 8.5.2, instructional safeguard requirements for moving parts, the
symbol for element 1a "shall be" IEC60417-6056 for moving fan blades and IEC
60417-6057 for other moving parts.   Suppose the moving part is something
like a rubber belt and these symbols do not convey that? 

 

Now if I look at the standard Clause F.5 for instructional safeguards, it
describes element 1a in Table F.1 more generally as a symbol that identifies
the nature of the class 2 or class 3 energy source and the consequences that
can be caused by the energy source.  It further states that symbols for
element 1a shall be from IEC 60417, ISO 3864-2, ISO 7000, ISO 7010 or the
equivalent.

 

My question then, is it permissible to select a symbol from the IEC/ISO
standards, other than the symbols specified in section 8.5.2, that clearly
the identifies the nature of the moving part or energy source?  In other
words can I ignore the "shall be" part of 8.5.2 and select a more
appropriate symbol from the IEC/ISO standards?   This same question applies
to instructional safeguards for other energy sources, as well.

 

Thank you.

 

Jim Hulbert 


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[PSES] correct URLs for Canada product certification rules

[Richard Nute]

In my earlier message, the URLs got split by my e-mail program.  Here are
the un-split URLs:

https://canada.ul.com/wp-content/uploads/sites/11/2018/05/Acceptance-of-Elec
trical-Products-in-Canada-1.pdf

http://www.scc.ca/en/accreditation/product-process-and-service-certification
/directory-of-accredited-clients

Rich



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Re: [PSES] Electrical safety testing US and Canada ... Mandatory ?

[Richard Nute]

Hi Amund:

In the USA, the federal government workplace rules and most other
jurisdictions require certification by a NRTL.  Most certification houses
are NRTL.  Here is the current list of NRTLs:

https://www.osha.gov/dts/otpca/nrtl/nrtllist.html

All NRTLs are "approved" for the standards specified in their "scope of
recognition" list in the NRTL web site.  

For Canada, see:

https://canada.ul.com/wp-content/uploads/sites/11/2018/05/Acceptance-of-Elec
trical-Products-in-Canada-1.pdf

http://www.scc.ca/en/accreditation/product-process-and-service-certification
/directory-of-accredited-clients

The first document is by UL, and may have some bias.  The second is the list
of accredited certification houses.  


stay safe, and best regards,
Rich




-Original Message-
From: Amund Westin  
Sent: Monday, May 25, 2020 6:09 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Electrical safety testing US and Canada ... Mandatory ?

Sorry for bringing up this issue again, but I have lost my history for all
previous IEEE mails  ...

I know (assume ...) that UL, CSA, FM and others are voluntary for showing
compliance.
But that is actually required by law in US and C?


Thanks!

Best regards
Amund

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Re: [PSES] 61010 vs 60601

[Richard Nute]

 

 

Hi Steve:

 

I would think that 60601-1 certification is sufficient, and that 61010-1 is not 
needed.  After all, 60601-1 *should be* the more severe standard.  

 

Some years ago, I certified a printer that was certified as EDP as medical 
equipment too.  Easy.

 

If you ask a certification house, they may look at the 60601-1 certification 
report, but they will probably start from scratch as they will claim that they 
don’t know whether the requirements are the same or equivalent.  Especially 
since the medical and measurement product groups at the certification house are 
different.  And, more revenue. 

 

I recently bought a S-VHS recorder/player that was for medical use and was 
UL-medical-equipment-certified that included a label “not for patient use.”   
I’m using it in my home despite not being certified the same as my other TV 
equipment.  I think its okay.  

 

Stay safe, and best regards,

Rich

 

 

From: sgbrody  
Sent: Thursday, May 21, 2020 12:16 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] 61010 vs 60601

 

Fellow gurus,

 

I have a client who has a product certified to 60601-1 and now they have a 
non-medical application and are looking for 61010-1.

 

Can the medical cert and report be leveraged towards 61010-1 or a new report be 
started from scratch?

 

Same for EMC.

 

Thanks,

 

 

 

 

Sent from my Verizon, Samsung Galaxy smartphone

 

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Re: [PSES] IEC 61010-1:2010 hazardous DC voltage

[Richard Nute]

 

Pete Perkins said:  “A major difficulty is that the body effects are from the 
current while the product committees would like to specify voltage, which is 
easier to measure and verify compliance.”  

 

I’ve had occasion to review a number of IEC safety standards for limits on 
voltage and current:

 

IEC 61010 

Safety requirements for electrical equipment for measurement, control, and 
laboratory use 

 

IEC 60950-1

Information technology equipment – Safety – Part 1: General requirements

 

IEC 60335-1

Household and similar electrical appliances – Safety – Part 1: General 
requirements

 

IEC 60065

Audio, video and similar electronic apparatus – Safety requirements

 

IEC 60601 

Medical electrical equipment – Part 1: General requirements for basic safety 
and essential performance

 

IEC 61347-1

Lamp controlgear – Part 1: General and safety requirements

 

IEC 62368-1

Audio/video, information and communication technology equipment – Part 1: 
Safety requirements

 

Each of these safety standards specifies limits for accessible voltages and 
currents.  If the prospective touch voltage exceeds a specified limit, the 
touch current must not exceed the specified limit.  The current requirement is 
not prominent in most of these safety standards. 

 

IEC 61347-1 specifies “effective touch voltage,” 34 volts peak maximum, by 
using a 50 k resistor; the current at 34 volts peak is 0.68 milliampere peak or 
0.48 milliampere rms.  One measurement, voltage, accounts for both touch 
voltage and touch current.  See Flore Chiang’s presentation at the 2012 
Symposium, “Prospective Touch Voltage.”

 

Best regards,

Rich

 

 

 


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Re: [PSES] IEC 61010-1:2010 hazardous DC voltage

[Richard Nute]

 

Hi Ian:

 

The hi-pot test voltages are from IEC 60664-1, Table F.5.  See IEC TR 62368-2, 
sub-clause 5.4.2.4.  

 

IEC 60664-1 is a “… a Basic Safety Publication intended for use by technical 
committees in the preparation of standards…”  See Table A.1 for derivation of 
the withstand voltages.  (The first edition of IEC 664 includes a table of air 
breakdown voltages as well as air withstand voltages.)  

 

Best regards,

Rich

 

 

From: McBurney, Ian  
Sent: Wednesday, February 26, 2020 1:24 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] IEC 61010-1:2010 hazardous DC voltage

 

Dear colleagues.

 

I would be interested in finding out how the hipot values (electric strength) 
were derived as they have been increased in 62368-1.

 

Regards;

 

Ian McBurney

Lead Compliance Engineer

Allen & Heath Ltd.

Kernick Industrial estate,

Penryn,

Cornwall. TR10 9LU. UK.

Tel: 01326 372070

Email: ian.mcbur...@allen-heath.com  

 


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